Messages in this thread Patch in this message | | | From | Paolo 'Blaisorblade' Giarrusso <> | Subject | [PATCH 3/5] uml: hostfs - fix possible PAGE_CACHE_SHIFT overflows | Date | Thu, 29 Dec 2005 17:39:57 +0100 |
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From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Prevent page->index << PAGE_CACHE_SHIFT from overflowing.
There is a casting there, but was added without care, so it's at the wrong place. Note the extra parens around the shift - "+" is higher precedence than "<<", leading to a GCC warning which saved all us.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> ---
fs/hostfs/hostfs_kern.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c index 3aac164..b3ad0bd 100644 --- a/fs/hostfs/hostfs_kern.c +++ b/fs/hostfs/hostfs_kern.c @@ -501,11 +501,16 @@ int hostfs_commit_write(struct file *fil long long start; int err = 0; - start = (long long) (page->index << PAGE_CACHE_SHIFT) + from; + start = (((long long) page->index) << PAGE_CACHE_SHIFT) + from; buffer = kmap(page); err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from, to - from); if(err > 0) err = 0; + + /* Actually, if !err, write_file has added to-from to start, so, despite + * the appearance, we are comparing i_size against the _last_ written + * location, as we should. */ + if(!err && (start > inode->i_size)) inode->i_size = start; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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