linux-kernel - [patch] vfs: check for integer overflows in posix_acl

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 24 Jun 2013 19:27:19 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Alexander Viro <viro@...iv.linux.org.uk>
Cc:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [patch] vfs: check for integer overflows in posix_acl_alloc()

We've seen cases where people passed negative numbers to
posix_acl_alloc() and we fixed the caller.  For example 093019cf1b "xfs:
fix acl count validation in xfs_acl_from_disk()".  But there are other
places which might be affected like ext4_acl_from_disk() which checks
for negative but doesn't check an upper limit.

Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index cea4623..cd7fd2f 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -46,7 +46,12 @@ posix_acl_alloc(int count, gfp_t flags)
 {
 	const size_t size = sizeof(struct posix_acl) +
 	                    count * sizeof(struct posix_acl_entry);
-	struct posix_acl *acl = kmalloc(size, flags);
+	struct posix_acl *acl;
+
+	if (count < 0 || count > (SIZE_MAX - sizeof(struct posix_acl) /
+					sizeof(struct posix_acl_entry)))
+		return NULL;
+	acl = kmalloc(size, flags);
 	if (acl)
 		posix_acl_init(acl, count);
 	return acl;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/