The patch titled
Fix /proc/pid/pagemap return length calculation
has been added to the -mm tree. Its filename is
maps2-add-proc-pid-pagemap-interface-fix-proc-pid-pagemap-return-length-calculation.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Fix /proc/pid/pagemap return length calculation
From: boutcher@xxxxxxxxxx (Dave Boutcher)
/proc/pid/pagemap has a header (usually 8 bytes) the length of which needs
to be compensated for when converting from proc file offset to page number.
The calculation of the starting page number (svpfn) compensates for this,
but the calculation of the ending page number (evpfn) does not, resulting
in reads returning 8 bytes more than were asked for and nastily overwriting
userspace memory.
Signed-off-by: Dave Boutcher <boutcher@xxxxxxxxxx>
Acked-by: Matt Mackall <mpm@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
diff -puN fs/proc/task_mmu.c~maps2-add-proc-pid-pagemap-interface-fix-proc-pid-pagemap-return-length-calculation fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~maps2-add-proc-pid-pagemap-interface-fix-proc-pid-pagemap-return-length-calculation
+++ a/fs/proc/task_mmu.c
@@ -659,7 +659,7 @@ static ssize_t pagemap_read(struct file
addr = PAGE_SIZE * svpfn;
if ((svpfn + 1) * sizeof(unsigned long) != src)
goto out;
- evpfn = min((src + count) / sizeof(unsigned long),
+ evpfn = min((src + count) / sizeof(unsigned long) - 1,
((~0UL) >> PAGE_SHIFT) + 1);
count = (evpfn - svpfn) * sizeof(unsigned long);
end = PAGE_SIZE * evpfn;
_
Patches currently in -mm which might be from boutcher@xxxxxxxxxx are
maps2-add-proc-pid-pagemap-interface-fix-proc-pid-pagemap-return-length-calculation.patch
-
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