# git rev-parse -q --verify 99793e64b815ec88daa9955c6347bd541e78543b^{commit} 99793e64b815ec88daa9955c6347bd541e78543b already have revision, skipping fetch # git checkout -q -f -B kisskb 99793e64b815ec88daa9955c6347bd541e78543b # git clean -qxdf # < git log -1 # commit 99793e64b815ec88daa9955c6347bd541e78543b # Author: Michael Ellerman # Date: Mon Mar 16 22:32:32 2020 +1100 # # powerpc/64: Prevent stack protection in early boot # # The previous commit reduced the amount of code that is run before we # setup a paca. However there are still a few remaining functions that # run with no paca, or worse, with an arbitrary value in r13 that will # be used as a paca pointer. # # In particular the stack protector canary is stored in the paca, so if # stack protector is activated for any of these functions we will read # the stack canary from wherever r13 points. If r13 happens to point # outside of memory we will get a machine check / checkstop. # # For example if we modify initialise_paca() to trigger stack # protection, and then boot in the mambo simulator with r13 poisoned in # skiboot before calling the kernel: # # DEBUG: 19952232: (19952232): INSTRUCTION: PC=0xC0000000191FC1E8: [0x3C4C006D]: addis r2,r12,0x6D [fetch] # DEBUG: 19952236: (19952236): INSTRUCTION: PC=0xC00000001807EAD8: [0x7D8802A6]: mflr r12 [fetch] # FATAL ERROR: 19952276: (19952276): Check Stop for 0:0: Machine Check with ME bit of MSR off # DEBUG: 19952276: (19952276): INSTRUCTION: PC=0xC0000000191FCA7C: [0xE90D0CF8]: ld r8,0xCF8(r13) [Instruction Failed] # INFO: 19952276: (19952277): ** Execution stopped: Mambo Error, Machine Check Stop, ** # systemsim % bt # pc: 0xC0000000191FCA7C initialise_paca+0x54 # lr: 0xC0000000191FC22C early_setup+0x44 # stack:0x00000000198CBED0 0x0 +0x0 # stack:0x00000000198CBF00 0xC0000000191FC22C early_setup+0x44 # stack:0x00000000198CBF90 0x1801C968 +0x1801C968 # # So annotate the relevant functions to ensure stack protection is never # enabled for them. # # Fixes: 06ec27aea9fc ("powerpc/64: add stack protector support") # Cc: stable@vger.kernel.org # v4.20+ # Signed-off-by: Michael Ellerman # < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-gcc --version # < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-ld --version # < git log --format=%s --max-count=1 99793e64b815ec88daa9955c6347bd541e78543b # < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_pmac32_defconfig+SMP_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- pmac32_defconfig # Added to kconfig CONFIG_SMP=y # < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_pmac32_defconfig+SMP_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- help # make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_pmac32_defconfig+SMP_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- olddefconfig .config:4058:warning: override: reassigning to symbol SMP # make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_pmac32_defconfig+SMP_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- /kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl': /kisskb/src/kernel/printk/printk.c:204:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/sound/ppc/awacs.c: In function 'snd_pmac_awacs_init': /kisskb/src/include/sound/control.h:218:2: warning: 'speaker_vol' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/sound/ppc/awacs.c:873:36: note: 'speaker_vol' was declared here /kisskb/src/fs/proc/inode.c: In function 'proc_reg_open': /kisskb/src/include/linux/list.h:72:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/proc/inode.c:338:21: note: 'pdeo' was declared here /kisskb/src/kernel/trace/trace_events.c: In function 'event_create_dir': /kisskb/src/kernel/trace/trace_events.c:2040:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/ext4/extents.c: In function 'ext4_convert_unwritten_io_end_vec': /kisskb/src/fs/ext4/extents.c:5009:23: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/tty/serial/8250/8250_core.c: In function 'univ8250_release_irq': /kisskb/src/drivers/tty/serial/8250/8250_core.c:248:18: warning: 'i' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/tty/serial/8250/8250_core.c:228:19: note: 'i' was declared here /kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c: In function 'drm_dp_mst_dsc_aux_for_port': /kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c:5400:9: warning: missing braces around initializer [-Wmissing-braces] /kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c:5400:9: warning: (near initialization for 'desc.ident') [-Wmissing-braces] /kisskb/src/fs/udf/unicode.c: In function 'udf_name_conv_char': /kisskb/src/fs/udf/unicode.c:132:8: warning: 'c' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/nfsd/nfs4xdr.c: In function 'nfsd4_encode_components_esc': /kisskb/src/fs/nfsd/nfs4xdr.c:2151:9: warning: 'str' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/usb/core/devio.c: In function 'async_completed': /kisskb/src/drivers/usb/core/devio.c:625:23: warning: 'errno' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/net/tun.c: In function 'tun_get_user': /kisskb/src/drivers/net/tun.c:1836:30: warning: 'copylen' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/net/tun.c:1749:46: warning: 'linear' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/net/wireless/broadcom/b43/phy_n.c: In function 'b43_nphy_rf_ctl_override_rev7': /kisskb/src/drivers/net/wireless/broadcom/b43/phy_n.c:190:21: warning: 'val_addr' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/io_uring.c: In function '__io_sqe_files_update.isra.64': /kisskb/src/fs/io_uring.c:5824:13: warning: 'err' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/mac80211/mlme.c: In function 'ieee80211_rx_mgmt_beacon': /kisskb/src/net/mac80211/mlme.c:1576:3: warning: 'pwr_level_cisco' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/mac80211/mlme.c:1533:6: note: 'pwr_level_cisco' was declared here INFO: Uncompressed kernel (size 0x8d50f4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x900000) Completed OK # rm -rf /kisskb/build/powerpc-next_pmac32_defconfig+SMP_powerpc-gcc4.6 # Build took: 0:01:31.685222