Use check_mul_overflow() to safely compute the total size of ELF program headers instead of relying on direct multiplication. Directly multiplying sizeof(struct elf_phdr) with e_phnum risks integer overflow, especially on 32-bit systems or with malformed ELF binaries crafted to trigger wrap-around. If an overflow occurs, kmalloc() could allocate insufficient memory, potentially leading to out-of-bound accesses, memory corruption or security vulnerabilities. Using check_mul_overflow() ensures the multiplication is performed safely and detects overflows before memory allocation. This change makes the function more robust when handling untrusted or corrupted binaries. Signed-off-by: Pranav Tyagi <pranav.tyagi03@xxxxxxxxx> Link: https://github.com/KSPP/linux/issues/92 --- fs/binfmt_elf.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index a43363d593e5..774e705798b8 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -518,7 +518,10 @@ static struct elf_phdr *load_elf_phdrs(const struct elfhdr *elf_ex, /* Sanity check the number of program headers... */ /* ...and their total size. */ - size = sizeof(struct elf_phdr) * elf_ex->e_phnum; + + if (check_mul_overflow(sizeof(struct elf_phdr), elf_ex->e_phnum, &size)) + goto out; + if (size == 0 || size > 65536 || size > ELF_MIN_ALIGN) goto out; -- 2.49.0
