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[173.164.112.133]) by smtp.gmail.com with ESMTPSA id b88sm38535857pfd.108.2018.03.07.19.31.27 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 07 Mar 2018 19:31:27 -0800 (PST) From: Kees Cook To: Andrew Morton Cc: Kees Cook , linux-kernel@vger.kernel.org, corbet@lwn.net, gustavo@embeddedor.com, rostedt@goodmis.org, Chris Mason , Josef Bacik , David Sterba , "David S. Miller" , Alexey Kuznetsov , Hideaki YOSHIFUJI , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Masahiro Yamada , Borislav Petkov , Josh Poimboeuf , Randy Dunlap , Ian Abbott , "Tobin C. Harding" , Sergey Senozhatsky , Petr Mladek , Andy Shevchenko , Pantelis Antoniou , linux-btrfs@vger.kernel.org, netdev@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [PATCH 3/3] btrfs: tree-checker: Avoid accidental stack VLA Date: Wed, 7 Mar 2018 19:30:47 -0800 Message-Id: <1520479847-39174-4-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1520479847-39174-1-git-send-email-keescook@chromium.org> References: <1520479847-39174-1-git-send-email-keescook@chromium.org> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In the quest to remove all stack VLAs from the kernel[1], this refactors the stack array size calculation to avoid using max(), which makes the compiler think the size isn't fixed. [1] https://lkml.org/lkml/2018/3/7/621 Signed-off-by: Kees Cook Acked-by: David Sterba --- fs/btrfs/tree-checker.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index c3c8d48f6618..59bd07694118 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -341,7 +341,8 @@ static int check_dir_item(struct btrfs_root *root, */ if (key->type == BTRFS_DIR_ITEM_KEY || key->type == BTRFS_XATTR_ITEM_KEY) { - char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)]; + char namebuf[SIMPLE_MAX(BTRFS_NAME_LEN, + XATTR_NAME_MAX)]; read_extent_buffer(leaf, namebuf, (unsigned long)(di + 1), name_len);