From 4448008eb12f4b6bb9993584de8ec1d20b708d6f Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 24 Nov 2010 11:19:05 -0800 Subject: [PATCH] isdn: icn: Fix stack corruption bug. Running randconfig with ktest.pl I hit this bug: [ 16.101158] ICN-ISDN-driver Rev 1.65.6.8 mem=0x000d0000 [ 16.106376] icn: (line0) ICN-2B, port 0x320 added [ 16.111064] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: c1642880 [ 16.111066] [ 16.121214] Pid: 1, comm: swapper Not tainted 2.6.37-rc2-test-00124-g6656b3f #8 [ 16.128499] Call Trace: [ 16.130942] [] ? printk+0x1d/0x23 [ 16.135200] [] panic+0x5c/0x162 [ 16.139286] [] ? icn_addcard+0x6d/0xbe [ 16.143975] [] print_tainted+0x0/0x8c [ 16.148582] [] ? icn_init+0xd8/0xdf [ 16.153012] [] icn_init+0xd8/0xdf [ 16.157271] [] do_one_initcall+0x8c/0x143 [ 16.162222] [] ? icn_init+0x0/0xdf [ 16.166566] [] kernel_init+0x13f/0x1da [ 16.171256] [] ? kernel_init+0x0/0x1da [ 16.175945] [] kernel_thread_helper+0x6/0x10 [ 16.181181] panic occurred, switching back to text console Looking into it I found that the stack was corrupted by the assignment of the Rev #. The variable rev is given 10 bytes, and in this output the characters that were copied was: " 1.65.6.8 $". Which was 11 characters plus the null ending character for a total of 12 bytes, thus corrupting the stack. This patch ups the variable size to 20 bytes as well as changes the strcpy to strncpy. I also added a check to make sure '$' is found. Signed-off-by: Steven Rostedt Signed-off-by: David S. Miller --- drivers/isdn/icn/icn.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/isdn/icn/icn.c b/drivers/isdn/icn/icn.c index 2e847a90bad0..f2b5bab5e6a1 100644 --- a/drivers/isdn/icn/icn.c +++ b/drivers/isdn/icn/icn.c @@ -1627,7 +1627,7 @@ __setup("icn=", icn_setup); static int __init icn_init(void) { char *p; - char rev[10]; + char rev[20]; memset(&dev, 0, sizeof(icn_dev)); dev.memaddr = (membase & 0x0ffc000); @@ -1637,9 +1637,10 @@ static int __init icn_init(void) spin_lock_init(&dev.devlock); if ((p = strchr(revision, ':'))) { - strcpy(rev, p + 1); + strncpy(rev, p + 1, 20); p = strchr(rev, '$'); - *p = 0; + if (p) + *p = 0; } else strcpy(rev, " ??? "); printk(KERN_NOTICE "ICN-ISDN-driver Rev%smem=0x%08lx\n", rev,