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ab7e8bb6e0
Found with grep. strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. We expect super->signature to be NUL-terminated based on its usage with memcmp against a NUL-term'd buffer: btt_devs.c: 253 | if (memcmp(super->signature, BTT_SIG, BTT_SIG_LEN) != 0) btt.h: 13 | #define BTT_SIG "BTT_ARENA_INFO\0" NUL-padding is not required as `super` is already zero-allocated: btt.c: 985 | super = kzalloc(sizeof(struct btt_sb), GFP_NOIO); ... rendering any additional NUL-padding superfluous. Considering the above, a suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. Let's also use the more idiomatic strscpy usage of (dest, src, sizeof(dest)) instead of (dest, src, XYZ_LEN) for buffers that the compiler can determine the size of. This more tightly correlates the destination buffer to the amount of bytes copied. Side note, this pattern of memcmp() on two NUL-terminated strings should really be changed to just a strncmp(), if i'm not mistaken? I see multiple instances of this pattern in this system: | if (memcmp(super->signature, BTT_SIG, BTT_SIG_LEN) != 0) | return false; where BIT_SIG is defined (weirdly) as a double NUL-terminated string: | #define BTT_SIG "BTT_ARENA_INFO\0" Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20231019-strncpy-drivers-nvdimm-btt-c-v2-1-366993878cf0@google.com Signed-off-by: Kees Cook <keescook@chromium.org> |
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| .. | ||
| badrange.c | ||
| btt_devs.c | ||
| btt.c | ||
| btt.h | ||
| bus.c | ||
| claim.c | ||
| core.c | ||
| dax_devs.c | ||
| dimm_devs.c | ||
| dimm.c | ||
| e820.c | ||
| Kconfig | ||
| label.c | ||
| label.h | ||
| Makefile | ||
| namespace_devs.c | ||
| nd_perf.c | ||
| nd_virtio.c | ||
| nd-core.h | ||
| nd.h | ||
| of_pmem.c | ||
| pfn_devs.c | ||
| pfn.h | ||
| pmem.c | ||
| pmem.h | ||
| region_devs.c | ||
| region.c | ||
| security.c | ||
| virtio_pmem.c | ||
| virtio_pmem.h | ||