Return-path: Received: from m1plsmtpa01-01.prod.mesa1.secureserver.net ([64.202.165.173]:57079 "EHLO m1plsmtpa01-01.prod.mesa1.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966032Ab3E2Tdd (ORCPT ); Wed, 29 May 2013 15:33:33 -0400 From: "Mark A. Greer" To: "John W. Linville" Cc: linux-wireless@vger.kernel.org, Bing Zhao , "Mark A. Greer" Subject: [PATCH] mwifiex: debugfs: Fix out of bounds array access Date: Wed, 29 May 2013 12:25:34 -0700 Message-Id: <1369855534-20897-1-git-send-email-mgreer@animalcreek.com> (sfid-20130529_213400_601638_69176ABF) Sender: linux-wireless-owner@vger.kernel.org List-ID: From: "Mark A. Greer" When reading the contents of '/sys/kernel/debug/mwifiex/p2p0/info', the following panic occurs: $ cat /sys/kernel/debug/mwifiex/p2p0/info Unable to handle kernel paging request at virtual address 74706164 pgd = de530000 [74706164] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM Modules linked in: phy_twl4030_usb omap2430 musb_hdrc mwifiex_sdio mwifiex CPU: 0 PID: 1635 Comm: cat Not tainted 3.10.0-rc1-00010-g1268390 #1 task: de16b6c0 ti: de048000 task.ti: de048000 PC is at strnlen+0xc/0x4c LR is at string+0x3c/0xf8 pc : [] lr : [] psr: a0000013 sp : de049e10 ip : c06efba0 fp : de6d2092 r10: bf01a260 r9 : ffffffff r8 : 74706164 r7 : 0000ffff r6 : ffffffff r5 : de6d209c r4 : 00000000 r3 : ff0a0004 r2 : 74706164 r1 : ffffffff r0 : 74706164 Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 10c5387d Table: 9e530019 DAC: 00000015 Process cat (pid: 1635, stack limit = 0xde048240) Stack: (0xde049e10 to 0xde04a000) 9e00: de6d2092 00000002 bf01a25e de6d209c 9e20: de049e80 c02c438c 0000000a ff0a0004 ffffffff 00000000 00000000 de049e48 9e40: 00000000 2192df6d ff0a0004 ffffffff 00000000 de6d2092 de049ef8 bef3cc00 9e60: de6b0000 dc358000 de6d2000 00000000 00000003 c02c45a4 bf01790c bf01a254 9e80: 74706164 bf018698 00000000 de59c3c0 de048000 de049f80 00001000 bef3cc00 9ea0: 00000008 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9ec0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9ee0: 00000000 00000000 00000000 00000001 00000000 00000000 6669776d 20786569 9f00: 20302e31 2e343128 392e3636 3231702e 00202933 00000000 00000003 c0294898 9f20: 00000000 00000000 00000000 00000000 de59c3c0 c0107c04 de554000 de59c3c0 9f40: 00001000 bef3cc00 de049f80 bef3cc00 de049f80 00000000 00000003 c0108a00 9f60: de048000 de59c3c0 00000000 00000000 de59c3c0 00001000 bef3cc00 c0108b60 9f80: 00000000 00000000 00001000 bef3cc00 00000003 00000003 c0014128 de048000 9fa0: 00000000 c0013f80 00001000 bef3cc00 00000003 bef3cc00 00001000 00000000 9fc0: 00001000 bef3cc00 00000003 00000003 00000001 00000001 00000001 00000003 9fe0: 00000000 bef3cbdc 00011984 b6f1127c 60000010 00000003 18dbdd2c 7f7bfffd [] (strnlen+0xc/0x4c) from [] (string+0x3c/0xf8) [] (string+0x3c/0xf8) from [] (vsnprintf+0x1e8/0x3e8) [] (vsnprintf+0x1e8/0x3e8) from [] (sprintf+0x18/0x24) [] (sprintf+0x18/0x24) from [] (mwifiex_info_read+0xfc/0x3e8 [mwifiex]) [] (mwifiex_info_read+0xfc/0x3e8 [mwifiex]) from [] (vfs_read+0xb0/0x144) [] (vfs_read+0xb0/0x144) from [] (SyS_read+0x44/0x70) [] (SyS_read+0x44/0x70) from [] (ret_fast_syscall+0x0/0x30) Code: e12fff1e e3510000 e1a02000 0a00000d (e5d03000) ---[ end trace ca98273dc605a04f ]--- The panic is caused by the mwifiex_info_read() routine assuming that there can only be four modes (0-3) which is an invalid assumption. For example, when testing P2P, the mode is '8' (P2P_CLIENT) so the code accesses data beyond the bounds of the bss_modes[] array which causes the panic. Fix this by updating bss_modes[] to support the current list of modes and adding a check to prevent the out-of-bounds access from occuring in the future when more modes are added. Signed-off-by: Mark A. Greer --- drivers/net/wireless/mwifiex/debugfs.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/drivers/net/wireless/mwifiex/debugfs.c b/drivers/net/wireless/mwifiex/debugfs.c index 753b568..a5f9875 100644 --- a/drivers/net/wireless/mwifiex/debugfs.c +++ b/drivers/net/wireless/mwifiex/debugfs.c @@ -26,10 +26,17 @@ static struct dentry *mwifiex_dfs_dir; static char *bss_modes[] = { - "Unknown", - "Ad-hoc", - "Managed", - "Auto" + "UNSPECIFIED", + "ADHOC", + "STATION", + "AP", + "AP_VLAN", + "WDS", + "MONITOR", + "MESH_POINT", + "P2P_CLIENT", + "P2P_GO", + "P2P_DEVICE", }; /* size/addr for mwifiex_debug_info */ @@ -200,7 +207,12 @@ mwifiex_info_read(struct file *file, char __user *ubuf, p += sprintf(p, "driver_version = %s", fmt); p += sprintf(p, "\nverext = %s", priv->version_str); p += sprintf(p, "\ninterface_name=\"%s\"\n", netdev->name); - p += sprintf(p, "bss_mode=\"%s\"\n", bss_modes[info.bss_mode]); + + if (info.bss_mode >= ARRAY_SIZE(bss_modes)) + p += sprintf(p, "bss_mode=\"%d\"\n", info.bss_mode); + else + p += sprintf(p, "bss_mode=\"%s\"\n", bss_modes[info.bss_mode]); + p += sprintf(p, "media_state=\"%s\"\n", (!priv->media_connected ? "Disconnected" : "Connected")); p += sprintf(p, "mac_address=\"%pM\"\n", netdev->dev_addr); -- 1.7.12