Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933547Ab2KZRKb (ORCPT ); Mon, 26 Nov 2012 12:10:31 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:47806 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933535Ab2KZRK1 (ORCPT ); Mon, 26 Nov 2012 12:10:27 -0500 From: Herton Ronaldo Krzesinski To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Sasha Levin , "J. Bruce Fields" , Herton Ronaldo Krzesinski Subject: [PATCH 169/270] SUNRPC: Prevent kernel stack corruption on long values of flush Date: Mon, 26 Nov 2012 14:57:39 -0200 Message-Id: <1353949160-26803-170-git-send-email-herton.krzesinski@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1353949160-26803-1-git-send-email-herton.krzesinski@canonical.com> References: <1353949160-26803-1-git-send-email-herton.krzesinski@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2498 Lines: 62 3.5.7u1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Sasha Levin commit 212ba90696ab4884e2025b0b13726d67aadc2cd4 upstream. The buffer size in read_flush() is too small for the longest possible values for it. This can lead to a kernel stack corruption: [ 43.047329] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff833e64b4 [ 43.047329] [ 43.049030] Pid: 6015, comm: trinity-child18 Tainted: G W 3.5.0-rc7-next-20120716-sasha #221 [ 43.050038] Call Trace: [ 43.050435] [] panic+0xcd/0x1f4 [ 43.050931] [] ? read_flush.isra.7+0xe4/0x100 [ 43.051602] [] __stack_chk_fail+0x16/0x20 [ 43.052206] [] read_flush.isra.7+0xe4/0x100 [ 43.052951] [] ? read_flush_pipefs+0x30/0x30 [ 43.053594] [] read_flush_procfs+0x2c/0x30 [ 43.053596] [] proc_reg_read+0x9c/0xd0 [ 43.053596] [] ? proc_reg_write+0xd0/0xd0 [ 43.053596] [] do_loop_readv_writev+0x4b/0x90 [ 43.053596] [] do_readv_writev+0xf6/0x1d0 [ 43.053596] [] vfs_readv+0x3e/0x60 [ 43.053596] [] sys_readv+0x48/0xb0 [ 43.053596] [] system_call_fastpath+0x1a/0x1f Signed-off-by: Sasha Levin Signed-off-by: J. Bruce Fields Signed-off-by: Herton Ronaldo Krzesinski --- net/sunrpc/cache.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index 47ad266..97bbcdc 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -1406,11 +1406,11 @@ static ssize_t read_flush(struct file *file, char __user *buf, size_t count, loff_t *ppos, struct cache_detail *cd) { - char tbuf[20]; + char tbuf[22]; unsigned long p = *ppos; size_t len; - sprintf(tbuf, "%lu\n", convert_to_wallclock(cd->flush_time)); + snprintf(tbuf, sizeof(tbuf), "%lu\n", convert_to_wallclock(cd->flush_time)); len = strlen(tbuf); if (p >= len) return 0; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/