# git rev-parse -q --verify cc7a0bb058b85ea03db87169c60c7cfdd5d34678^{commit}
cc7a0bb058b85ea03db87169c60c7cfdd5d34678
already have revision, skipping fetch
# git checkout -q -f -B kisskb cc7a0bb058b85ea03db87169c60c7cfdd5d34678
# git clean -qxdf
# < git log -1
# commit cc7a0bb058b85ea03db87169c60c7cfdd5d34678
# Author: Tyrel Datwyler <tyreld@linux.ibm.com>
# Date:   Mon Mar 15 15:48:21 2021 -0600
# 
#     PCI: rpadlpar: Fix potential drc_name corruption in store functions
#     
#     Both add_slot_store() and remove_slot_store() try to fix up the
#     drc_name copied from the store buffer by placing a NUL terminator at
#     nbyte + 1 or in place of a '\n' if present. However, the static buffer
#     that we copy the drc_name data into is not zeroed and can contain
#     anything past the n-th byte.
#     
#     This is problematic if a '\n' byte appears in that buffer after nbytes
#     and the string copied into the store buffer was not NUL terminated to
#     start with as the strchr() search for a '\n' byte will mark this
#     incorrectly as the end of the drc_name string resulting in a drc_name
#     string that contains garbage data after the n-th byte.
#     
#     Additionally it will cause us to overwrite that '\n' byte on the stack
#     with NUL, potentially corrupting data on the stack.
#     
#     The following debugging shows an example of the drmgr utility writing
#     "PHB 4543" to the add_slot sysfs attribute, but add_slot_store()
#     logging a corrupted string value.
#     
#       drmgr: drmgr: -c phb -a -s PHB 4543 -d 1
#       add_slot_store: drc_name = PHB 4543°|<82>!, rc = -19
#     
#     Fix this by using strscpy() instead of memcpy() to ensure the string
#     is NUL terminated when copied into the static drc_name buffer.
#     Further, since the string is now NUL terminated the code only needs to
#     change '\n' to '\0' when present.
#     
#     Cc: stable@vger.kernel.org
#     Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
#     [mpe: Reformat change log and add mention of possible stack corruption]
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20210315214821.452959-1-tyreld@linux.ibm.com
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 cc7a0bb058b85ea03db87169c60c7cfdd5d34678
# < make -s -j 10 ARCH=powerpc O=/kisskb/build/powerpc-fixes_holly_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  holly_defconfig
# < make -s -j 10 ARCH=powerpc O=/kisskb/build/powerpc-fixes_holly_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 10 ARCH=powerpc O=/kisskb/build/powerpc-fixes_holly_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
# make -s -j 10 ARCH=powerpc O=/kisskb/build/powerpc-fixes_holly_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
INFO: Uncompressed kernel (size 0x6cda60) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0x700000)
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_holly_defconfig_powerpc-gcc5
# Build took: 0:01:02.273193