Messages in this thread | | | From | Joe Lawrence <> | Subject | [PATCH v3 0/4] A few round_pipe_size() and pipe-max-size fixups | Date | Tue, 10 Oct 2017 14:04:45 -0400 |
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While backporting Michael's "pipe: fix limit handling" patchset to a distro-kernel, Mikulas noticed that current upstream pipe limit handling contains a few problems:
1 - procfs signed wrap: echo'ing a large number into /proc/sys/fs/pipe-max-size and then cat'ing it back out shows a negative value.
2 - round_pipe_size() nr_pages overflow on 32bit: this would subsequently try roundup_pow_of_two(0), which is undefined.
3 - visible non-rounded pipe-max-size value: there is no mutual exclusion or protection between the time pipe_max_size is assigned a raw value from proc_dointvec_minmax() and when it is rounded.
4 - unsigned long -> unsigned int conversion makes for potential odd return errors from do_proc_douintvec_minmax_conv() and do_proc_dopipe_max_size_conv().
This version underwent the same testing as v1: https://marc.info/?l=linux-kernel&m=150643571406022&w=2
v1 (from rfc):
- Re-arrange patchset order, push smaller fixes to the front - Add a check so that round_pipe_size(size < pipe_min_size) will round up to round_pipe_size(pipe_min_size) as per man page [RD] - Add new procfs proc_dopipe_max_size() and helpers to consolidate user space read / type validation / rounding / assignment [MP]
v2: - Fix !CONFIG_PROC_SYSCTL build case [buildbots]
v3: - s/proc_dointvec_minmax/proc_dopipe_max_size/ in comment preceding pipe_proc_fn() - Added a fourth patch to address -ERANGE vs. -EINVAL inconsistencies in do_proc_douintvec_minmax_conv() and do_proc_dopipe_max_size_conv().
Joe Lawrence (4): pipe: match pipe_max_size data type with procfs pipe: avoid round_pipe_size() nr_pages overflow on 32-bit pipe: add proc_dopipe_max_size() to safely assign pipe_max_size sysctl: check for UINT_MAX before unsigned int min/max
fs/pipe.c | 23 ++++++++++--------- include/linux/pipe_fs_i.h | 1 + include/linux/sysctl.h | 3 +++ kernel/sysctl.c | 57 ++++++++++++++++++++++++++++++++++++++++++++--- 4 files changed, 70 insertions(+), 14 deletions(-)
-- 1.8.3.1
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