diff options
| author | Kees Cook <keescook@chromium.org> | 2016-01-20 15:00:45 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-05 14:37:16 +0200 |
| commit | 2449a71eb98204fc54ff55ddd6825cc5141ce176 (patch) | |
| tree | 3606a48b264afec20beb16d41f2171fc276bbf85 | |
| parent | 1e0f216195a6d106ed50c386abffdf60f496d518 (diff) | |
sysctl: enable strict writes
commit 41662f5cc55335807d39404371cfcbb1909304c4 upstream.
SYSCTL_WRITES_WARN was added in commit f4aacea2f5d1 ("sysctl: allow for
strict write position handling"), and released in v3.16 in August of
2014. Since then I can find only 1 instance of non-zero offset
writing[1], and it was fixed immediately in CRIU[2]. As such, it
appears safe to flip this to the strict state now.
[1] https://www.google.com/search?q="when%20file%20position%20was%20not%200"
[2] http://lists.openvz.org/pipermail/criu/2015-April/019819.html
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | Documentation/sysctl/kernel.txt | 15 | ||||
| -rw-r--r-- | kernel/sysctl.c | 2 |
2 files changed, 8 insertions, 9 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index af70d1541d3a..be61d53e997f 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -810,14 +810,13 @@ via the /proc/sys interface: Each write syscall must fully contain the sysctl value to be written, and multiple writes on the same sysctl file descriptor will rewrite the sysctl value, regardless of file position. - 0 - (default) Same behavior as above, but warn about processes that - perform writes to a sysctl file descriptor when the file position - is not 0. - 1 - Respect file position when writing sysctl strings. Multiple writes - will append to the sysctl value buffer. Anything past the max length - of the sysctl value buffer will be ignored. Writes to numeric sysctl - entries must always be at file position 0 and the value must be - fully contained in the buffer sent in the write syscall. + 0 - Same behavior as above, but warn about processes that perform writes + to a sysctl file descriptor when the file position is not 0. + 1 - (default) Respect file position when writing sysctl strings. Multiple + writes will append to the sysctl value buffer. Anything past the max + length of the sysctl value buffer will be ignored. Writes to numeric + sysctl entries must always be at file position 0 and the value must + be fully contained in the buffer sent in the write syscall. ============================================================== diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 300d64162aff..464a7864e4c5 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -174,7 +174,7 @@ extern int no_unaligned_warning; #define SYSCTL_WRITES_WARN 0 #define SYSCTL_WRITES_STRICT 1 -static int sysctl_writes_strict = SYSCTL_WRITES_WARN; +static int sysctl_writes_strict = SYSCTL_WRITES_STRICT; static int proc_do_cad_pid(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); |