fs: afs: Fix a possible null-pointer dereference in afs_put_read()
In afs_read_dir(), there is an if statement on line 255 to check whether
req->pages is NULL:
if (!req->pages)
goto error;
If req->pages is NULL, afs_put_read() on line 337 is executed.
In afs_put_read(), req->pages[i] is used on line 195.
Thus, a possible null-pointer dereference may occur in this case.
To fix this possible bug, an if statement is added in afs_put_read() to
check req->pages.
This bug is found by a static analysis tool STCheck written by us.
Fixes: f3ddee8dc4
("afs: Fix directory handling")
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
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@ -191,11 +191,13 @@ void afs_put_read(struct afs_read *req)
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int i;
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int i;
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if (refcount_dec_and_test(&req->usage)) {
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if (refcount_dec_and_test(&req->usage)) {
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for (i = 0; i < req->nr_pages; i++)
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if (req->pages) {
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if (req->pages[i])
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for (i = 0; i < req->nr_pages; i++)
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put_page(req->pages[i]);
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if (req->pages[i])
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if (req->pages != req->array)
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put_page(req->pages[i]);
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kfree(req->pages);
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if (req->pages != req->array)
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kfree(req->pages);
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}
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kfree(req);
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kfree(req);
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}
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}
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}
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}
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