Messages in this thread Patch in this message | | | From | Shuah Khan <> | Subject | [PATCH v2] module: fix validate_section_offset() overflow bug on 64-bit | Date | Mon, 18 Oct 2021 11:35:11 -0600 |
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validate_section_offset() uses unsigned long local variable to add/store shdr->sh_offset and shdr->sh_size on all platforms. unsigned long is too short when sh_offset is Elf64_Off which would be the case on 64bit ELF headers.
This problem was found while adding an error message to print sh_offset and sh_size. If sh_offset + sh_size exceed the size of the local variable, the checks for overflow and offset/size being too large will not find the problem and call the section offset valid. This failure might cause problems later on.
Fix the overflow problem using the right size local variable when CONFIG_64BIT is defined.
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> --- Changes since v1: - Updated commit log to describe the fix clearly. No code changes.
kernel/module.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/kernel/module.c b/kernel/module.c index ad03a2357377..84a9141a5e15 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2942,7 +2942,11 @@ static int module_sig_check(struct load_info *info, int flags) static int validate_section_offset(struct load_info *info, Elf_Shdr *shdr) { +#if defined(CONFIG_64BIT) + unsigned long long secend; +#else unsigned long secend; +#endif /* * Check for both overflow and offset/size being -- 2.30.2
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