# git rev-parse -q --verify c7ce5fe9288c5692fa456a804cf5ea5976d842f1^{commit} c7ce5fe9288c5692fa456a804cf5ea5976d842f1 already have revision, skipping fetch # git checkout -q -f -B kisskb c7ce5fe9288c5692fa456a804cf5ea5976d842f1 # git clean -qxdf # < git log -1 # commit c7ce5fe9288c5692fa456a804cf5ea5976d842f1 # Author: Michael Neuling # Date: Fri Jul 19 15:05:02 2019 +1000 # # powerpc/tm: Fix oops on sigreturn on systems without TM # # On systems like P9 powernv where we have no TM (or P8 booted with # ppc_tm=off), userspace can construct a signal context which still has # the MSR TS bits set. The kernel tries to restore this context which # results in the following crash: # # Unexpected TM Bad Thing exception at c0000000000022fc (msr 0x8000000102a03031) tm_scratch=800000020280f033 # Oops: Unrecoverable exception, sig: 6 [#1] # LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries # Modules linked in: # CPU: 0 PID: 1636 Comm: sigfuz Not tainted 5.2.0-11043-g0a8ad0ffa4 #69 # NIP: c0000000000022fc LR: 00007fffb2d67e48 CTR: 0000000000000000 # REGS: c00000003fffbd70 TRAP: 0700 Not tainted (5.2.0-11045-g7142b497d8) # MSR: 8000000102a03031 CR: 42004242 XER: 00000000 # CFAR: c0000000000022e0 IRQMASK: 0 # GPR00: 0000000000000072 00007fffb2b6e560 00007fffb2d87f00 0000000000000669 # GPR04: 00007fffb2b6e728 0000000000000000 0000000000000000 00007fffb2b6f2a8 # GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 # GPR12: 0000000000000000 00007fffb2b76900 0000000000000000 0000000000000000 # GPR16: 00007fffb2370000 00007fffb2d84390 00007fffea3a15ac 000001000a250420 # GPR20: 00007fffb2b6f260 0000000010001770 0000000000000000 0000000000000000 # GPR24: 00007fffb2d843a0 00007fffea3a14a0 0000000000010000 0000000000800000 # GPR28: 00007fffea3a14d8 00000000003d0f00 0000000000000000 00007fffb2b6e728 # NIP [c0000000000022fc] rfi_flush_fallback+0x7c/0x80 # LR [00007fffb2d67e48] 0x7fffb2d67e48 # Call Trace: # Instruction dump: # e96a0220 e96a02a8 e96a0330 e96a03b8 394a0400 4200ffdc 7d2903a6 e92d0c00 # e94d0c08 e96d0c10 e82d0c18 7db242a6 <4c000024> 7db243a6 7db142a6 f82d0c18 # # The problem is the signal code assumes TM is enabled when # CONFIG_PPC_TRANSACTIONAL_MEM is enabled. This may not be the case as # with P9 powernv or if `ppc_tm=off` is used on P8. # # This means any local user can crash the system. # # Fix the problem by returning a bad stack frame to the user if they try # to set the MSR TS bits with sigreturn() on systems where TM is not # supported. # # Found with sigfuz kernel selftest on P9. # # This fixes CVE-2019-13648. # # Fixes: 2b0a576d15e0 ("powerpc: Add new transactional memory state to the signal context") # # NOTE: fixes commit 2b0a576d15e0 released in v3.9. # # Consider a stable tag: # # Cc: stable@vger.kernel.org # v3.9+ # Cc: stable@vger.kernel.org # v3.9 # Reported-by: Praveen Pandey # Signed-off-by: Michael Neuling # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/20190719050502.405-1-mikey@neuling.org # < /opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux-gcc --version # < /opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux-ld --version # < git log --format=%s --max-count=1 c7ce5fe9288c5692fa456a804cf5ea5976d842f1 # < make -s -j 120 ARCH=arm64 O=/kisskb/build/powerpc-fixes_arm64-defconfig_arm64-gcc5.4 CROSS_COMPILE=/opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux- defconfig # make -s -j 120 ARCH=arm64 O=/kisskb/build/powerpc-fixes_arm64-defconfig_arm64-gcc5.4 CROSS_COMPILE=/opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux- arch/arm64/Makefile:27: ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum arch/arm64/Makefile:38: LSE atomics not supported by binutils arch/arm64/Makefile:56: CROSS_COMPILE_COMPAT not defined or empty, the compat vDSO will not be built /kisskb/src/drivers/i2c/busses/i2c-sh_mobile.c: In function 'sh_mobile_i2c_isr': /kisskb/src/drivers/i2c/busses/i2c-sh_mobile.c:399:26: warning: 'data' may be used uninitialized in this function [-Wmaybe-uninitialized] pd->msg->buf[real_pos] = data; ^ /kisskb/src/drivers/i2c/busses/i2c-sh_mobile.c:372:16: note: 'data' was declared here unsigned char data; ^ In file included from /kisskb/src/include/linux/rwsem.h:16:0, from /kisskb/src/include/linux/notifier.h:15, from /kisskb/src/include/linux/clk.h:14, from /kisskb/src/drivers/tty/serial/sh-sci.c:24: /kisskb/src/drivers/tty/serial/sh-sci.c: In function 'sci_dma_rx_submit': /kisskb/src/include/linux/spinlock.h:288:3: warning: 'flags' may be used uninitialized in this function [-Wmaybe-uninitialized] _raw_spin_unlock_irqrestore(lock, flags); \ ^ /kisskb/src/drivers/tty/serial/sh-sci.c:1353:16: note: 'flags' was declared here unsigned long flags; ^ Completed OK # rm -rf /kisskb/build/powerpc-fixes_arm64-defconfig_arm64-gcc5.4 # Build took: 0:02:31.789945