# git rev-parse -q --verify d41a3effbb53b1bcea41e328d16a4d046a508381^{commit}
d41a3effbb53b1bcea41e328d16a4d046a508381
already have revision, skipping fetch
# git checkout -q -f -B kisskb d41a3effbb53b1bcea41e328d16a4d046a508381
# git clean -qxdf
# < git log -1
# commit d41a3effbb53b1bcea41e328d16a4d046a508381
# Author: Hillf Danton <hdanton@sina.com>
# Date:   Mon Sep 2 13:37:29 2019 +0100
# 
#     keys: Fix missing null pointer check in request_key_auth_describe()
#     
#     If a request_key authentication token key gets revoked, there's a window in
#     which request_key_auth_describe() can see it with a NULL payload - but it
#     makes no check for this and something like the following oops may occur:
#     
#             BUG: Kernel NULL pointer dereference at 0x00000038
#             Faulting instruction address: 0xc0000000004ddf30
#             Oops: Kernel access of bad area, sig: 11 [#1]
#             ...
#             NIP [...] request_key_auth_describe+0x90/0xd0
#             LR [...] request_key_auth_describe+0x54/0xd0
#             Call Trace:
#             [...] request_key_auth_describe+0x54/0xd0 (unreliable)
#             [...] proc_keys_show+0x308/0x4c0
#             [...] seq_read+0x3d0/0x540
#             [...] proc_reg_read+0x90/0x110
#             [...] __vfs_read+0x3c/0x70
#             [...] vfs_read+0xb4/0x1b0
#             [...] ksys_read+0x7c/0x130
#             [...] system_call+0x5c/0x70
#     
#     Fix this by checking for a NULL pointer when describing such a key.
#     
#     Also make the read routine check for a NULL pointer to be on the safe side.
#     
#     [DH: Modified to not take already-held rcu lock and modified to also check
#      in the read routine]
#     
#     Fixes: 04c567d9313e ("[PATCH] Keys: Fix race between two instantiators of a key")
#     Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
#     Signed-off-by: Hillf Danton <hdanton@sina.com>
#     Signed-off-by: David Howells <dhowells@redhat.com>
#     Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-ld --version
# < git log --format=%s --max-count=1 d41a3effbb53b1bcea41e328d16a4d046a508381
# < make -s -j 32 ARCH=arm O=/kisskb/build/linus_raumfeld_defconfig_arm CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-  raumfeld_defconfig
***
*** Can't find default configuration "arch/arm/configs/raumfeld_defconfig"!
***
make[2]: *** [/kisskb/src/scripts/kconfig/Makefile:90: raumfeld_defconfig] Error 1
make[1]: *** [/kisskb/src/Makefile:562: raumfeld_defconfig] Error 2
make: *** [Makefile:179: sub-make] Error 2
Command 'make -s -j 32 ARCH=arm O=/kisskb/build/linus_raumfeld_defconfig_arm CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-  raumfeld_defconfig' returned non-zero exit status 2
# rm -rf /kisskb/build/linus_raumfeld_defconfig_arm
# Build took: 0:00:02.097594