Fix UB in test_unistd_write_broken_link #23125
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The test was failing under ASan because no null byte was being read from the file, so the strlen inside printf was running off the buffer. It just happened to work on non-ASan because wasm memory is initialized to zero.
sbc100
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Dec 10, 2024
sbc100
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Dec 10, 2024
| int src_fd = open("link_source", O_CREAT | O_WRONLY, 0777); | ||
| printf("source_fd: %d, errno: %d %s\n", src_fd, errno, strerror(errno)); | ||
| write(src_fd, "abc", 3); | ||
| write(src_fd, "abc\0", 4); |
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Seems a little odd to write null byte to a text file.. but I guess its not important here.
sbc100
reviewed
Dec 10, 2024
| { | ||
| int target_fd = open("link_source", O_RDONLY); | ||
| printf("target_fd: %d, errno: %d %s\n", target_fd, errno, strerror(errno)); | ||
| char buf[10]; |
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An alternative here I suppose would be intialize buf on the stack with char buf[10] = { '\0' };
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Yeah, I could go either way on that, do you have a preference?
sbc100
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Dec 10, 2024
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|
Thanks! |
hedwigz
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Dec 18, 2024
The test was failing under ASan because no null byte was being read from the file, so the strlen inside printf was running off the buffer. It just happened to work on non-ASan because wasm memory is initialized to zero.
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The test was failing under ASan because no null byte was being
read from the file, so the strlen inside printf was running
off the buffer. It just happened to work on non-ASan because
wasm memory is initialized to zero.