3.16.57-rc1 review patch. If anyone has any objections, please let me know.
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From: Eric Biggers ebiggers@google.com
commit 96e99be40e4cff870a83233731121ec0f7f95075 upstream.
A pipe's size is represented as an 'unsigned int'. As expected, writing a value greater than UINT_MAX to /proc/sys/fs/pipe-max-size fails with EINVAL. However, the F_SETPIPE_SZ fcntl silently truncates such values to 32 bits, rather than failing with EINVAL as expected. (It *does* fail with EINVAL for values above (1 << 31) but <= UINT_MAX.)
Fix this by moving the check against UINT_MAX into round_pipe_size() which is called in both cases.
Link: http://lkml.kernel.org/r/20180111052902.14409-6-ebiggers3@gmail.com Signed-off-by: Eric Biggers ebiggers@google.com Acked-by: Kees Cook keescook@chromium.org Acked-by: Joe Lawrence joe.lawrence@redhat.com Cc: Alexander Viro viro@zeniv.linux.org.uk Cc: "Luis R . Rodriguez" mcgrof@kernel.org Cc: Michael Kerrisk mtk.manpages@gmail.com Cc: Mikulas Patocka mpatocka@redhat.com Cc: Willy Tarreau w@1wt.eu Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Ben Hutchings ben@decadent.org.uk --- fs/pipe.c | 5 ++++- include/linux/pipe_fs_i.h | 2 +- kernel/sysctl.c | 3 --- 3 files changed, 5 insertions(+), 5 deletions(-)
--- a/fs/pipe.c +++ b/fs/pipe.c @@ -1008,10 +1008,13 @@ const struct file_operations pipefifo_fo * Currently we rely on the pipe array holding a power-of-2 number * of pages. Returns 0 on error. */ -unsigned int round_pipe_size(unsigned int size) +unsigned int round_pipe_size(unsigned long size) { unsigned long nr_pages;
+ if (size > UINT_MAX) + return 0; + /* Minimum pipe size, as required by POSIX */ if (size < PAGE_SIZE) size = PAGE_SIZE; --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -148,6 +148,6 @@ long pipe_fcntl(struct file *, unsigned struct pipe_inode_info *get_pipe_info(struct file *file);
int create_pipe_files(struct file **, int); -unsigned int round_pipe_size(unsigned int size); +unsigned int round_pipe_size(unsigned long size);
#endif --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2230,9 +2230,6 @@ static int do_proc_dopipe_max_size_conv( if (write) { unsigned int val;
- if (*lvalp > UINT_MAX) - return -EINVAL; - val = round_pipe_size(*lvalp); if (*negp || val == 0) return -EINVAL;