4.16-stable review patch. If anyone has any objections, please let me know.
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From: Rob Gardner rob.gardner@oracle.com
[ Upstream commit 49d7006d9f01d435661d03bbea3db4c33935b3d8 ]
Each Oracle DAX CCB has a corresponding completion area, and the required number of areas must fit within a previously allocated array of completion areas beginning at the requested index. Since the completion area index is specified by a file offset, a user can pass arbitrary values, including negative numbers. So the index must be thoroughly range checked to prevent access to addresses outside the bounds of the allocated completion area array. The index cannot be negative, and it cannot exceed the total array size, less the number of CCBs requested. The old code did not check for negative values and was off by one on the upper bound.
Signed-off-by: Rob Gardner rob.gardner@oracle.com Signed-off-by: Jonathan Helman jonathan.helman@oracle.com Reported-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/sbus/char/oradax.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/sbus/char/oradax.c +++ b/drivers/sbus/char/oradax.c @@ -880,7 +880,7 @@ static int dax_ccb_exec(struct dax_ctx * dax_dbg("args: ccb_buf_len=%ld, idx=%d", count, idx);
/* for given index and length, verify ca_buf range exists */ - if (idx + nccbs >= DAX_CA_ELEMS) { + if (idx < 0 || idx > (DAX_CA_ELEMS - nccbs)) { ctx->result.exec.status = DAX_SUBMIT_ERR_NO_CA_AVAIL; return 0; }