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sh_eth: fix kernel oops in skb_put()

PATCH Applied Sergei Shtylyov 2 participants 4 messages Dec 3, 2015 – Dec 14, 2015

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Sergei Shtylyov

author
#0 lore raw

PATCH v3 1/1 sh_eth: fix kernel oops in skb_put()

In a low memory situation the following kernel oops occurs:

Unable to handle kernel NULL pointer dereference at virtual address 00000050
pgd = 8490c000
[00000050] *pgdF51e831, *pte000000, *ppte000000
Internal error: Oops: 17 [#1] PREEMPT ARM
Modules linked in:
CPU: 0    Not tainted  (3.4-at16 #9)
PC is at skb_put+0x10/0x98
LR is at sh_eth_poll+0x2c8/0xa10
pc : [<8035f780>]    lr : [<8028bf50>]    psr: 60000113

sp : 84eb1a90 ip : 84eb1ac8 fp : 84eb1ac4
r10: 0000003f r9 : 000005ea r8 : 00000000
r7 : 00000000 r6 : 940453b0 r5 : 00030000 r4 : 9381b180 r3 : 00000000 r2 : 00000000 r1 : 000005ea r0 : 00000000
Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
Control: 10c53c7d Table: 4248c059 DAC: 00000015 Process klogd (pid: 2046, stack limit = 0x84eb02e8) [...]

This is because netdev_alloc_skb() fails and 'mdp->rx_skbuff[entry]' is left NULL but sh_eth_rx() later uses it without checking. Add such check...

Reported-by Yasushi SHOJI <[email protected]>
Signed-off-by Sergei Shtylyov <[email protected]>

---
The patch is against Dave Miller's 'net.git' repo.

Changes in version 3:
- refreshed the patch;
- reformatted the changelog;
- removed [RFT] from the subject.

Changes in version 2:
- moved reading 'mdp->rx_skbuff[entry]' earlier to avoid *goto*.

drivers/net/ethernet/renesas/sh_eth.c | 4 ++--

 drivers/net/ethernet/renesas/sh_eth.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: net/drivers/net/ethernet/renesas/sh_eth.c =================================--- net.orig/drivers/net/ethernet/renesas/sh_eth.c +++ net/drivers/net/ethernet/renesas/sh_eth.c
@@ -1462,6 +1462,7 @@ static int sh_eth_rx(struct net_device *
if (mdp->cd->shift_rd0)
desc_status >>= 16;

+ skb = mdp->rx_skbuff[entry];
if (desc_status & (RD_RFS1 | RD_RFS2 | RD_RFS3 | RD_RFS4 |
RD_RFS5 | RD_RFS6 | RD_RFS10)) {
ndev->stats.rx_errors++;
@@ -1477,12 +1478,11 @@ static int sh_eth_rx(struct net_device *
ndev->stats.rx_missed_errors++;
if (desc_status & RD_RFS10)
ndev->stats.rx_over_errors++;
- } else {
+ } else if (skb) {
if (!mdp->cd->hw_swap)
sh_eth_soft_swap(
phys_to_virt(ALIGN(rxdesc->addr, 4)), pkt_len + 2);
- skb = mdp->rx_skbuff[entry];
mdp->rx_skbuff[entry] = NULL;
if (mdp->cd->rpadir)
skb_reserve(skb, NET_IP_ALIGN);

maintainer Applied
#1 lore raw

From: Sergei Shtylyov <[email protected]>
Date: Fri, 04 Dec 2015 01:45:40 +0300

Quoted 20 lines

In a low memory situation the following kernel oops occurs:

Unable to handle kernel NULL pointer dereference at virtual address 00000050
pgd = 8490c000
[00000050] *pgdF51e831, *pte000000, *ppte000000
Internal error: Oops: 17 [#1] PREEMPT ARM
Modules linked in:
CPU: 0    Not tainted  (3.4-at16 #9)
PC is at skb_put+0x10/0x98
LR is at sh_eth_poll+0x2c8/0xa10
pc : [<8035f780>]    lr : [<8028bf50>]    psr: 60000113

sp : 84eb1a90 ip : 84eb1ac8 fp : 84eb1ac4
r10: 0000003f r9 : 000005ea r8 : 00000000
r7 : 00000000 r6 : 940453b0 r5 : 00030000 r4 : 9381b180 r3 : 00000000 r2 : 00000000 r1 : 000005ea r0 : 00000000
Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
Control: 10c53c7d Table: 4248c059 DAC: 00000015 Process klogd (pid: 2046, stack limit = 0x84eb02e8) [...]

Quoted 5 lines

This is because netdev_alloc_skb() fails and 'mdp->rx_skbuff[entry]' is left NULL but sh_eth_rx() later uses it without checking. Add such check...

Reported-by Yasushi SHOJI <[email protected]>
Signed-off-by Sergei Shtylyov <[email protected]>

Applied.

author
#2 lore raw

Hello.

Quoted 20 lines · David Miller
Quoted 20 lines

In a low memory situation the following kernel oops occurs:

Unable to handle kernel NULL pointer dereference at virtual address 00000050
pgd = 8490c000
[00000050] *pgdF51e831, *pte000000, *ppte000000
Internal error: Oops: 17 [#1] PREEMPT ARM
Modules linked in:
CPU: 0    Not tainted  (3.4-at16 #9)
PC is at skb_put+0x10/0x98
LR is at sh_eth_poll+0x2c8/0xa10
pc : [<8035f780>]    lr : [<8028bf50>]    psr: 60000113

sp : 84eb1a90 ip : 84eb1ac8 fp : 84eb1ac4
r10: 0000003f r9 : 000005ea r8 : 00000000
r7 : 00000000 r6 : 940453b0 r5 : 00030000 r4 : 9381b180 r3 : 00000000 r2 : 00000000 r1 : 000005ea r0 : 00000000
Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
Control: 10c53c7d Table: 4248c059 DAC: 00000015 Process klogd (pid: 2046, stack limit = 0x84eb02e8) [...]

Quoted 7 lines
Quoted 5 lines

This is because netdev_alloc_skb() fails and 'mdp->rx_skbuff[entry]' is left NULL but sh_eth_rx() later uses it without checking. Add such check...

Reported-by Yasushi SHOJI <[email protected]>
Signed-off-by Sergei Shtylyov <[email protected]>

Applied.

Could you also queue this for the stable kernels?

MBR, Sergei

maintainer
#3 lore raw

From: Sergei Shtylyov <[email protected]>
Date: Sat, 12 Dec 2015 18:17:45 +0300

Quoted 30 lines

Hello.

Quoted 26 lines · David Miller
Quoted 26 lines

In a low memory situation the following kernel oops occurs:

Unable to handle kernel NULL pointer dereference at virtual address
00000050
pgd = 8490c000
[00000050] *pgdF51e831, *pte000000, *ppte000000
Internal error: Oops: 17 [#1] PREEMPT ARM
Modules linked in:
CPU: 0    Not tainted  (3.4-at16 #9)
PC is at skb_put+0x10/0x98
LR is at sh_eth_poll+0x2c8/0xa10
pc : [<8035f780>]    lr : [<8028bf50>]    psr: 60000113

sp : 84eb1a90 ip : 84eb1ac8 fp : 84eb1ac4
r10: 0000003f r9 : 000005ea r8 : 00000000
r7 : 00000000 r6 : 940453b0 r5 : 00030000 r4 : 9381b180 r3 : 00000000 r2 : 00000000 r1 : 000005ea r0 : 00000000
Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
Control: 10c53c7d Table: 4248c059 DAC: 00000015 Process klogd (pid: 2046, stack limit = 0x84eb02e8) [...]

This is because netdev_alloc_skb() fails and 'mdp->rx_skbuff[entry]' is left
NULL but sh_eth_rx() later uses it without checking. Add such check...

Quoted 6 lines
Quoted 4 lines
Quoted 2 lines
Reported-by Yasushi SHOJI <[email protected]>
Signed-off-by Sergei Shtylyov <[email protected]>

Applied.

Could you also queue this for the stable kernels?

Done.