From 9e81eccf199d910e5ea8db377a43478e4eccd033 Mon Sep 17 00:00:00 2001 From: Christian Lamparter Date: Sun, 19 Jul 2009 05:05:37 +0200 Subject: [PATCH] cfg80211: double free in __cfg80211_scan_done This patch fixes a double free corruption in __cfg80211_scan_done: ================================================ BUG kmalloc-512: Object already free ------------------------------------------------ INFO: Allocated in load_elf_binary+0x18b/0x19af age=6 INFO: Freed in load_elf_binary+0x104e/0x19af age=5 INFO: Slab 0xffffea0001bae4c0 objects=14 used=7 INFO: Object 0xffff88007e8a9918 @offset=6424 fp=0xffff88007e8a9488 Bytes b4 0xffff88007e8a9908: 00 00 00 00 00 00 00 00 5a 5a [...] Pid: 28705, comm: rmmod Tainted: P C 2.6.31-rc2-wl #1 Call Trace: [] print_trailer+0x14e/0x16e [] object_err+0x42/0x61 [] __slab_free+0x2af/0x396 [] ? wiphy_unregister+0x92/0x142 [cfg80211] [] kfree+0x13c/0x17a [] ? wiphy_unregister+0x92/0x142 [cfg80211] [] wiphy_unregister+0x92/0x142 [cfg80211] [] ieee80211_unregister_hw+0xc8/0xff [mac80211] [] p54_unregister_common+0x31/0x66 [p54common] [...] FIX kmalloc-512: Object at 0xffff88007e8a9918 not freed The code path which leads to the *funny* double free: request = rdev->scan_req; dev = dev_get_by_index(&init_net, request->ifidx); /* * the driver was unloaded recently and * therefore dev_get_by_index will return NULL! */ if (!dev) goto out; [...] rdev->scan_req = NULL; /* not executed... */ [...] out: kfree(request); Signed-off-by: Christian Lamparter Signed-off-by: John W. Linville --- net/wireless/scan.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index f8e71b30000..9271118e1fc 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -35,8 +35,6 @@ void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted) else nl80211_send_scan_done(wiphy_to_dev(request->wiphy), dev); - wiphy_to_dev(request->wiphy)->scan_req = NULL; - #ifdef CONFIG_WIRELESS_EXT if (!aborted) { memset(&wrqu, 0, sizeof(wrqu)); @@ -48,6 +46,7 @@ void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted) dev_put(dev); out: + wiphy_to_dev(request->wiphy)->scan_req = NULL; kfree(request); } EXPORT_SYMBOL(cfg80211_scan_done); -- 2.11.4.GIT