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cve/meltdown: use the snprintf function to prevent buffer overflow #1079

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cve/meltdown: use the snprintf function to prevent buffer overflow #1079

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2 changes: 1 addition & 1 deletion testcases/cve/meltdown.c
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Original file line number Diff line number Diff line change
Expand Up @@ -281,7 +281,7 @@ find_kernel_symbol(const char *name)

if (uname(&utsname) < 0)
tst_brk(TBROK | TERRNO, "uname");
sprintf(systemmap, "/boot/System.map-%s", utsname.release);
snprintf(systemmap, sizeof(systemmap), "/boot/System.map-%s", utsname.release);
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systemmap is supposed to be null terminated. So you must reserve one byte for null and set it to zero.

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Actually as far as I can tell snprintf() always null terminates the output buffer, unless of course the buffer size passed is 0. So this patch looks good to me.

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@KunWuChan the patch is fine, but misses the signed-off-my line. See: https://www.kernel.org/doc/html/latest/process/submitting-patches.html?highlight=signed%20off#developer-s-certificate-of-origin-1-1

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thanks, I've update the comment.

addr = find_symbol_in_file(systemmap, name);
return addr;
}
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