user/sven/linux.git/fs/proc/array.c, branch v4.9.284

fs/proc/array.c: allow reporting eip/esp for all coredumping threads

2019-07-10T07:55:38Z

commit cb8f381f1613cafe3aec30809991cd56e7135d92 upstream. 0a1eb2d474ed ("fs/proc: Stop reporting eip and esp in /proc/PID/stat") stopped reporting eip/esp and fd7d56270b52 ("fs/proc: Report eip/esp in /prod/PID/stat for coredumping") reintroduced the feature to fix a regression with userspace core dump handlers (such as minicoredumper). Because PF_DUMPCORE is only set for the primary thread, this didn't fix the original problem for secondary threads. Allow reporting the eip/esp for all threads by checking for PF_EXITING as well. This is set for all the other threads when they are killed. coredump_wait() waits for all the tasks to become inactive before proceeding to invoke a core dumper. Link: http://lkml.kernel.org/r/87y32p7i7a.fsf@linutronix.de Link: http://lkml.kernel.org/r/20190522161614.628-1-jlu@pengutronix.de Fixes: fd7d56270b526ca3 ("fs/proc: Report eip/esp in /prod/PID/stat for coredumping") Signed-off-by: John Ogness Reported-by: Jan Luebbe Tested-by: Jan Luebbe Cc: Alexey Dobriyan Cc: Andy Lutomirski Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

proc: Remove empty line in /proc/self/status

2019-01-23T07:10:53Z

If CONFIG_SECCOMP=n, /proc/self/status includes an empty line. This causes the iotop application to bail out with an error message. File "/usr/local/lib64/python2.7/site-packages/iotop/data.py", line 196, in parse_proc_pid_status key, value = line.split(':\t', 1) ValueError: need more than 1 value to unpack The problem is seen in v4.9.y but not upstream because commit af884cd4a5ae6 ("proc: report no_new_privs state") has not been backported to v4.9.y. The backport of commit fae1fa0fc6cc ("proc: Provide details on speculation flaw mitigations") tried to address the resulting differences but was wrong, introducing the problem. Fixes: 51ef9af2a35b ("proc: Provide details on speculation flaw mitigations") Cc: Kees Cook Cc: Gwendal Grignou Signed-off-by: Guenter Roeck Acked-by: Kees Cook

proc: Use underscores for SSBD in 'status'

2018-05-22T14:58:02Z

commit e96f46ee8587607a828f783daa6eb5b44d25004d upstream The style for the 'status' file is CamelCase or this. _. Fixes: fae1fa0fc ("proc: Provide details on speculation flaw mitigations") Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Thomas Gleixner Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman

prctl: Add force disable speculation

2018-05-22T14:58:01Z

commit 356e4bfff2c5489e016fdb925adbf12a1e3950ee upstream For certain use cases it is desired to enforce mitigations so they cannot be undone afterwards. That's important for loader stubs which want to prevent a child from disabling the mitigation again. Will also be used for seccomp(). The extra state preserving of the prctl state for SSB is a preparatory step for EBPF dymanic speculation control. Signed-off-by: Thomas Gleixner Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman

proc: Provide details on speculation flaw mitigations

2018-05-22T14:58:01Z

commit fae1fa0fc6cca8beee3ab8ed71d54f9a78fa3f64 upstream As done with seccomp and no_new_privs, also show speculation flaw mitigation state in /proc/$pid/status. Signed-off-by: Kees Cook Signed-off-by: Thomas Gleixner Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman

proc: fix coredump vs read /proc/*/stat race

2018-01-23T18:57:08Z

commit 8bb2ee192e482c5d500df9f2b1b26a560bd3026f upstream. do_task_stat() accesses IP and SP of a task without bumping reference count of a stack (which became an entity with independent lifetime at some point). Steps to reproduce: #include #include #include #include #include #include #include #include int main(void) { setrlimit(RLIMIT_CORE, &(struct rlimit){}); while (1) { char buf[64]; char buf2[4096]; pid_t pid; int fd; pid = fork(); if (pid == 0) { *(volatile int *)0 = 0; } snprintf(buf, sizeof(buf), "/proc/%u/stat", pid); fd = open(buf, O_RDONLY); read(fd, buf2, sizeof(buf2)); close(fd); waitpid(pid, NULL, 0); } return 0; } BUG: unable to handle kernel paging request at 0000000000003fd8 IP: do_task_stat+0x8b4/0xaf0 PGD 800000003d73e067 P4D 800000003d73e067 PUD 3d558067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 1417 Comm: a.out Not tainted 4.15.0-rc8-dirty #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc27 04/01/2014 RIP: 0010:do_task_stat+0x8b4/0xaf0 Call Trace: proc_single_show+0x43/0x70 seq_read+0xe6/0x3b0 __vfs_read+0x1e/0x120 vfs_read+0x84/0x110 SyS_read+0x3d/0xa0 entry_SYSCALL_64_fastpath+0x13/0x6c RIP: 0033:0x7f4d7928cba0 RSP: 002b:00007ffddb245158 EFLAGS: 00000246 Code: 03 b7 a0 01 00 00 4c 8b 4c 24 70 4c 8b 44 24 78 4c 89 74 24 18 e9 91 f9 ff ff f6 45 4d 02 0f 84 fd f7 ff ff 48 8b 45 40 48 89 ef <48> 8b 80 d8 3f 00 00 48 89 44 24 20 e8 9b 97 eb ff 48 89 44 24 RIP: do_task_stat+0x8b4/0xaf0 RSP: ffffc90000607cc8 CR2: 0000000000003fd8 John Ogness said: for my tests I added an else case to verify that the race is hit and correctly mitigated. Link: http://lkml.kernel.org/r/20180116175054.GA11513@avx2 Signed-off-by: Alexey Dobriyan Reported-by: "Kohli, Gaurav" Tested-by: John Ogness Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

fs/proc: Report eip/esp in /prod/PID/stat for coredumping

2017-10-05T07:43:58Z

commit fd7d56270b526ca3ed0c224362e3c64a0f86687a upstream. Commit 0a1eb2d474ed ("fs/proc: Stop reporting eip and esp in /proc/PID/stat") stopped reporting eip/esp because it is racy and dangerous for executing tasks. The comment adds: As far as I know, there are no use programs that make any material use of these fields, so just get rid of them. However, existing userspace core-dump-handler applications (for example, minicoredumper) are using these fields since they provide an excellent cross-platform interface to these valuable pointers. So that commit introduced a user space visible regression. Partially revert the change and make the readout possible for tasks with the proper permissions and only if the target task has the PF_DUMPCORE flag set. Fixes: 0a1eb2d474ed ("fs/proc: Stop reporting eip and esp in> /proc/PID/stat") Reported-by: Marco Felsch Signed-off-by: John Ogness Reviewed-by: Andy Lutomirski Cc: Tycho Andersen Cc: Kees Cook Cc: Peter Zijlstra Cc: Brian Gerst Cc: Tetsuo Handa Cc: Borislav Petkov Cc: Al Viro Cc: Linux API Cc: Andrew Morton Cc: Linus Torvalds Link: http://lkml.kernel.org/r/87poatfwg6.fsf@linutronix.de Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

fs/proc: Stop reporting eip and esp in /proc/PID/stat

2016-10-20T07:21:41Z

Reporting these fields on a non-current task is dangerous. If the task is in any state other than normal kernel code, they may contain garbage or even kernel addresses on some architectures. (x86_64 used to do this. I bet lots of architectures still do.) With CONFIG_THREAD_INFO_IN_TASK=y, it can OOPS, too. As far as I know, there are no use programs that make any material use of these fields, so just get rid of them. Reported-by: Jann Horn Signed-off-by: Andy Lutomirski Acked-by: Thomas Gleixner Cc: Al Viro Cc: Andrew Morton Cc: Borislav Petkov Cc: Brian Gerst Cc: Kees Cook Cc: Linus Torvalds Cc: Linux API Cc: Peter Zijlstra Cc: Tetsuo Handa Cc: Tycho Andersen Link: http://lkml.kernel.org/r/a5fed4c3f4e33ed25d4bb03567e329bc5a712bcc.1475257877.git.luto@kernel.org Signed-off-by: Ingo Molnar

cred: simpler, 1D supplementary groups

2016-10-08T01:46:30Z

Current supplementary groups code can massively overallocate memory and is implemented in a way so that access to individual gid is done via 2D array. If number of gids is <= 32, memory allocation is more or less tolerable (140/148 bytes). But if it is not, code allocates full page (!) regardless and, what's even more fun, doesn't reuse small 32-entry array. 2D array means dependent shifts, loads and LEAs without possibility to optimize them (gid is never known at compile time). All of the above is unnecessary. Switch to the usual trailing-zero-len-array scheme. Memory is allocated with kmalloc/vmalloc() and only as much as needed. Accesses become simpler (LEA 8(gi,idx,4) or even without displacement). Maximum number of gids is 65536 which translates to 256KB+8 bytes. I think kernel can handle such allocation. On my usual desktop system with whole 9 (nine) aux groups, struct group_info shrinks from 148 bytes to 44 bytes, yay! Nice side effects: - "gi->gid[i]" is shorter than "GROUP_AT(gi, i)", less typing, - fix little mess in net/ipv4/ping.c should have been using GROUP_AT macro but this point becomes moot, - aux group allocation is persistent and should be accounted as such. Link: http://lkml.kernel.org/r/20160817201927.GA2096@p183.telecom.by Signed-off-by: Alexey Dobriyan Cc: Vasily Kulikov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

seq/proc: modify seq_put_decimal_[u]ll to take a const char *, not char

2016-10-08T01:46:30Z

Allow some seq_puts removals by taking a string instead of a single char. [akpm@linux-foundation.org: update vmstat_show(), per Joe] Link: http://lkml.kernel.org/r/667e1cf3d436de91a5698170a1e98d882905e956.1470704995.git.joe@perches.com Signed-off-by: Joe Perches Cc: Joe Perches Cc: Andi Kleen Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds