Messages in this thread Patch in this message | | | Date | Wed, 06 May 2009 13:30:18 -0700 | From | Greg KH <> | Subject | [patch 08/18] pagemap: require aligned-length, non-null reads of /proc/pid/pagemap |
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2.6.27-stable review patch. If anyone has any objections, please let us know.
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From: Vitaly Mayatskikh <v.mayatskih@gmail.com>
commit 0816178638c15ce5472d39d771a96860dff4141a upstream.
The intention of commit aae8679b0ebcaa92f99c1c3cb0cd651594a43915 ("pagemap: fix bug in add_to_pagemap, require aligned-length reads of /proc/pid/pagemap") was to force reads of /proc/pid/pagemap to be a multiple of 8 bytes, but now it allows to read 0 bytes, which actually puts some data to user's buffer. According to POSIX, if count is zero, read() should return zero and has no other results.
Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com> Cc: Thomas Tuttle <ttuttle@google.com> Acked-by: Matt Mackall <mpm@selenic.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/proc/task_mmu.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -665,6 +665,10 @@ static ssize_t pagemap_read(struct file goto out_task; ret = 0; + + if (!count) + goto out_task; + mm = get_task_mm(task); if (!mm) goto out_task;
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