Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.18 14/34] IB/ucm: Fix Spectre v1 vulnerability | Date | Thu, 8 Nov 2018 13:52:43 -0800 |
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4.18-stable review patch. If anyone has any objections, please let me know.
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From: Gustavo A. R. Silva <gustavo@embeddedor.com>
commit 0295e39595e1146522f2722715dba7f7fba42217 upstream.
hdr.cmd can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability.
This issue was detected with the help of Smatch:
drivers/infiniband/core/ucm.c:1127 ib_ucm_write() warn: potential spectre issue 'ucm_cmd_table' [r] (local cap)
Fix this by sanitizing hdr.cmd before using it to index ucm_cmd_table.
Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1].
[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/infiniband/core/ucm.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/infiniband/core/ucm.c +++ b/drivers/infiniband/core/ucm.c @@ -46,6 +46,8 @@ #include <linux/mutex.h> #include <linux/slab.h> +#include <linux/nospec.h> + #include <linux/uaccess.h> #include <rdma/ib.h> @@ -1123,6 +1125,7 @@ static ssize_t ib_ucm_write(struct file if (hdr.cmd >= ARRAY_SIZE(ucm_cmd_table)) return -EINVAL; + hdr.cmd = array_index_nospec(hdr.cmd, ARRAY_SIZE(ucm_cmd_table)); if (hdr.in + sizeof(hdr) > len) return -EINVAL;
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