From c21737bbff0da88f07feae4ad067fbc5983d8dfc Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 4 Dec 2024 15:07:15 +0300 Subject: [PATCH] binfmt_flat: Fix integer overflow bug on 32 bit systems BugLink: https://bugs.launchpad.net/bugs/2114239 commit 55cf2f4b945f6a6416cc2524ba740b83cc9af25a upstream. 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 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Noah Wager Signed-off-by: Mehmet Basaran --- fs/binfmt_flat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c index cd6d5bbb4b9d..3f740d8abb4f 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;