From: Dan Carpenter Date: Wed, 4 Dec 2024 12:07:15 +0000 (+0300) Subject: binfmt_flat: Fix integer overflow bug on 32 bit systems X-Git-Tag: v6.14-rc1~206^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=55cf2f4b945f6a6416cc2524ba740b83cc9af25a;p=thirdparty%2Fkernel%2Flinux.git binfmt_flat: Fix integer overflow bug on 32 bit systems Most of these sizes and counts are capped at 256MB so the math doesn't result in an integer overflow. The "relocs" count needs to be checked as well. Otherwise on 32bit systems the calculation of "full_data" could be wrong. full_data = data_len + relocs * sizeof(unsigned long); Fixes: c995ee28d29d ("binfmt_flat: prevent kernel dammage from corrupted executable headers") Cc: stable@vger.kernel.org Signed-off-by: Dan Carpenter Acked-by: Nicolas Pitre Link: https://lore.kernel.org/r/5be17f6c-5338-43be-91ef-650153b975cb@stanley.mountain Signed-off-by: Kees Cook --- diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c index 390808ce935d5..b5b5ca1a44f70 100644 --- a/fs/binfmt_flat.c +++ b/fs/binfmt_flat.c @@ -478,7 +478,7 @@ static int load_flat_file(struct linux_binprm *bprm, * 28 bits (256 MB) is way more than reasonable in this case. * If some top bits are set we have probable binary corruption. */ - if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) { + if ((text_len | data_len | bss_len | stack_len | relocs | full_data) >> 28) { pr_err("bad header\n"); ret = -ENOEXEC; goto err;