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authorMatthew Wilcox (Oracle) <willy@infradead.org>2020-01-31 05:07:55 -0500
committerMatthew Wilcox (Oracle) <willy@infradead.org>2020-01-31 15:09:36 -0500
commitbd40b17ca49d7d110adf456e647701ce74de2241 (patch)
tree5b08f821b4204ae3698a8763f63a8d66b73da381 /lib/xarray.c
parentd5226fa6dbae0569ee43ecfc08bdcd6770fc4755 (diff)
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XArray: Fix xa_find_next for large multi-index entries
Coverity pointed out that xas_sibling() was shifting xa_offset without promoting it to an unsigned long first, so the shift could cause an overflow and we'd get the wrong answer. The fix is obvious, and the new test-case provokes UBSAN to report an error: runtime error: shift exponent 60 is too large for 32-bit type 'int' Fixes: 19c30f4dd092 ("XArray: Fix xa_find_after with multi-index entries") Reported-by: Bjorn Helgaas <bhelgaas@google.com> Reported-by: Kees Cook <keescook@chromium.org> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: stable@vger.kernel.org
Diffstat (limited to 'lib/xarray.c')
-rw-r--r--lib/xarray.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/lib/xarray.c b/lib/xarray.c
index 1d9fab7db8da..acd1fad2e862 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1839,7 +1839,8 @@ static bool xas_sibling(struct xa_state *xas)
if (!node)
return false;
mask = (XA_CHUNK_SIZE << node->shift) - 1;
- return (xas->xa_index & mask) > (xas->xa_offset << node->shift);
+ return (xas->xa_index & mask) >
+ ((unsigned long)xas->xa_offset << node->shift);
}
/**