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| author | Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> | 2005-12-29 17:39:57 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-12-29 09:48:15 -0800 |
| commit | 30f04a4efa73dc80bf3f59f3f19ad5a24ac5ac0a (patch) | |
| tree | 0f7f165bcf73bf26f782a2b56d05020ea6d4d5b0 | |
| parent | 3d0a07e3310c947c048bd01d8d0efa0e4fae5ba9 (diff) | |
| download | linux-30f04a4efa73dc80bf3f59f3f19ad5a24ac5ac0a.tar.bz2 | |
[PATCH] uml: hostfs - fix possible PAGE_CACHE_SHIFT overflows
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>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | 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 3aac164c7726..b3ad0bd0312f 100644 --- a/fs/hostfs/hostfs_kern.c +++ b/fs/hostfs/hostfs_kern.c @@ -501,11 +501,16 @@ int hostfs_commit_write(struct file *file, struct page *page, unsigned from, 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; |