Buildresult: linus/xtensa-defconfig/xtensa-gcc8 built on Jan 9 2019, 13:18
kisskb
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Status:
OK
Date/Time:
Jan 9 2019, 13:18
Duration:
0:00:35.375083
Builder:
ka1
Revision:
fork: record start_time late (
7b55851367136b1efd84d98fea81ba57a98304cf)
Target:
linus/xtensa-defconfig/xtensa-gcc8
Branch:
linus
Compiler:
xtensa-gcc8
(xtensa-linux-gcc.br_real (Buildroot 2016.11-git-00613-ge98b4dd) 5.4.0 / GNU ld (GNU Binutils) 2.26.1)
Config:
defconfig
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Log:
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Possible warnings (3)
drivers/staging/mt7621-dts/Kconfig:4:warning: 'BUILTIN_DTB' has wrong type. 'select' only accept arguments of bool and tristate type <stdin>:1333:2: warning: #warning syscall io_pgetevents not implemented [-Wcpp] <stdin>:1336:2: warning: #warning syscall rseq not implemented [-Wcpp]
Full Log
# git rev-parse -q --verify 7b55851367136b1efd84d98fea81ba57a98304cf^{commit} 7b55851367136b1efd84d98fea81ba57a98304cf already have revision, skipping fetch # git checkout -q -f -B kisskb 7b55851367136b1efd84d98fea81ba57a98304cf # git clean -qxdf # < git log -1 # commit 7b55851367136b1efd84d98fea81ba57a98304cf # Author: David Herrmann <dh.herrmann@gmail.com> # Date: Tue Jan 8 13:58:52 2019 +0100 # # fork: record start_time late # # This changes the fork(2) syscall to record the process start_time after # initializing the basic task structure but still before making the new # process visible to user-space. # # Technically, we could record the start_time anytime during fork(2). But # this might lead to scenarios where a start_time is recorded long before # a process becomes visible to user-space. For instance, with # userfaultfd(2) and TLS, user-space can delay the execution of fork(2) # for an indefinite amount of time (and will, if this causes network # access, or similar). # # By recording the start_time late, it much closer reflects the point in # time where the process becomes live and can be observed by other # processes. # # Lastly, this makes it much harder for user-space to predict and control # the start_time they get assigned. Previously, user-space could fork a # process and stall it in copy_thread_tls() before its pid is allocated, # but after its start_time is recorded. This can be misused to later-on # cycle through PIDs and resume the stalled fork(2) yielding a process # that has the same pid and start_time as a process that existed before. # This can be used to circumvent security systems that identify processes # by their pid+start_time combination. # # Even though user-space was always aware that start_time recording is # flaky (but several projects are known to still rely on start_time-based # identification), changing the start_time to be recorded late will help # mitigate existing attacks and make it much harder for user-space to # control the start_time a process gets assigned. # # Reported-by: Jann Horn <jannh@google.com> # Signed-off-by: Tom Gundersen <teg@jklm.no> # Signed-off-by: David Herrmann <dh.herrmann@gmail.com> # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-gcc --version # < /opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-ld --version # < git log --format=%s --max-count=1 7b55851367136b1efd84d98fea81ba57a98304cf # < make -s -j 8 ARCH=xtensa O=/kisskb/build/linus_xtensa-defconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux- defconfig drivers/staging/mt7621-dts/Kconfig:4:warning: 'BUILTIN_DTB' has wrong type. 'select' only accept arguments of bool and tristate type # make -s -j 8 ARCH=xtensa O=/kisskb/build/linus_xtensa-defconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux- <stdin>:1333:2: warning: #warning syscall io_pgetevents not implemented [-Wcpp] <stdin>:1336:2: warning: #warning syscall rseq not implemented [-Wcpp] Completed OK # rm -rf /kisskb/build/linus_xtensa-defconfig_xtensa # Build took: 0:00:35.375083
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