From baf8fb577e042f4cd87f0ab5a30350ad11df4e74 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@linaro.org>
Date: Wed, 4 Dec 2024 15:07:15 +0300
Subject: [PATCH] binfmt_flat: Fix integer overflow bug on 32 bit systems
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 <dan.carpenter@linaro.org>
Acked-by: Nicolas Pitre <npitre@baylibre.com>
Link: https://lore.kernel.org/r/5be17f6c-5338-43be-91ef-650153b975cb@stanley.mountain
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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 cd6d5bbb4b9df..3f740d8abb4fe 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;
--
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