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authorAlexey Kodanev <alexey.kodanev@oracle.com>2015-03-11 14:29:17 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-03-26 15:00:55 +0100
commite2f572a9be3f00bcf470a918d9e53353bea9ef4c (patch)
tree2c7425e1a677f88366753a90e113f54d3a7a17ba /net
parent1ca2893325f9015fc85b1537a17402e33fb03473 (diff)
downloadlinux-linaro-stable-e2f572a9be3f00bcf470a918d9e53353bea9ef4c.tar.gz
net: sysctl_net_core: check SNDBUF and RCVBUF for min length
[ Upstream commit b1cb59cf2efe7971d3d72a7b963d09a512d994c9 ] sysctl has sysctl.net.core.rmem_*/wmem_* parameters which can be set to incorrect values. Given that 'struct sk_buff' allocates from rcvbuf, incorrectly set buffer length could result to memory allocation failures. For example, set them as follows: # sysctl net.core.rmem_default=64 net.core.wmem_default = 64 # sysctl net.core.wmem_default=64 net.core.wmem_default = 64 # ping localhost -s 1024 -i 0 > /dev/null This could result to the following failure: skbuff: skb_over_panic: text:ffffffff81628db4 len:-32 put:-32 head:ffff88003a1cc200 data:ffff88003a1cc200 tail:0xffffffe0 end:0xc0 dev:<NULL> kernel BUG at net/core/skbuff.c:102! invalid opcode: 0000 [#1] SMP ... task: ffff88003b7f5550 ti: ffff88003ae88000 task.ti: ffff88003ae88000 RIP: 0010:[<ffffffff8155fbd1>] [<ffffffff8155fbd1>] skb_put+0xa1/0xb0 RSP: 0018:ffff88003ae8bc68 EFLAGS: 00010296 RAX: 000000000000008d RBX: 00000000ffffffe0 RCX: 0000000000000000 RDX: ffff88003fdcf598 RSI: ffff88003fdcd9c8 RDI: ffff88003fdcd9c8 RBP: ffff88003ae8bc88 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 00000000000002b2 R12: 0000000000000000 R13: 0000000000000000 R14: ffff88003d3f7300 R15: ffff88000012a900 FS: 00007fa0e2b4a840(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000d0f7e0 CR3: 000000003b8fb000 CR4: 00000000000006f0 Stack: ffff88003a1cc200 00000000ffffffe0 00000000000000c0 ffffffff818cab1d ffff88003ae8bd68 ffffffff81628db4 ffff88003ae8bd48 ffff88003b7f5550 ffff880031a09408 ffff88003b7f5550 ffff88000012aa48 ffff88000012ab00 Call Trace: [<ffffffff81628db4>] unix_stream_sendmsg+0x2c4/0x470 [<ffffffff81556f56>] sock_write_iter+0x146/0x160 [<ffffffff811d9612>] new_sync_write+0x92/0xd0 [<ffffffff811d9cd6>] vfs_write+0xd6/0x180 [<ffffffff811da499>] SyS_write+0x59/0xd0 [<ffffffff81651532>] system_call_fastpath+0x12/0x17 Code: 00 00 48 89 44 24 10 8b 87 c8 00 00 00 48 89 44 24 08 48 8b 87 d8 00 00 00 48 c7 c7 30 db 91 81 48 89 04 24 31 c0 e8 4f a8 0e 00 <0f> 0b eb fe 66 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 48 83 RIP [<ffffffff8155fbd1>] skb_put+0xa1/0xb0 RSP <ffff88003ae8bc68> Kernel panic - not syncing: Fatal exception Moreover, the possible minimum is 1, so we can get another kernel panic: ... BUG: unable to handle kernel paging request at ffff88013caee5c0 IP: [<ffffffff815604cf>] __alloc_skb+0x12f/0x1f0 ... Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/sysctl_net_core.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 2ff093b7c45e..0a327b66a344 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -23,6 +23,8 @@
static int zero = 0;
static int one = 1;
static int ushort_max = USHRT_MAX;
+static int min_sndbuf = SOCK_MIN_SNDBUF;
+static int min_rcvbuf = SOCK_MIN_RCVBUF;
#ifdef CONFIG_RPS
static int rps_sock_flow_sysctl(ctl_table *table, int write,
@@ -97,7 +99,7 @@ static struct ctl_table net_core_table[] = {
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
- .extra1 = &one,
+ .extra1 = &min_sndbuf,
},
{
.procname = "rmem_max",
@@ -105,7 +107,7 @@ static struct ctl_table net_core_table[] = {
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
- .extra1 = &one,
+ .extra1 = &min_rcvbuf,
},
{
.procname = "wmem_default",
@@ -113,7 +115,7 @@ static struct ctl_table net_core_table[] = {
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
- .extra1 = &one,
+ .extra1 = &min_sndbuf,
},
{
.procname = "rmem_default",
@@ -121,7 +123,7 @@ static struct ctl_table net_core_table[] = {
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
- .extra1 = &one,
+ .extra1 = &min_rcvbuf,
},
{
.procname = "dev_weight",