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authorYann Droneaud <ydroneaud@opteya.com>2013-12-11 23:01:47 +0100
committerRoland Dreier <roland@purestorage.com>2013-12-20 10:54:30 -0800
commit7efb1b19b3414d7dec792f39e1c1a7db57a23961 (patch)
tree77b433b0ff851446bf5a5b29d44bd03bd4d65b00 /drivers
parenta96e4e2ffe439e45732d820fac6fee486b6412bf (diff)
downloadlinux-7efb1b19b3414d7dec792f39e1c1a7db57a23961.tar.bz2
IB/uverbs: Check reserved field in extended command header
As noted by Daniel Vetter in its article "Botching up ioctls"[1] "Check *all* unused fields and flags and all the padding for whether it's 0, and reject the ioctl if that's not the case. Otherwise your nice plan for future extensions is going right down the gutters since someone *will* submit an ioctl struct with random stack garbage in the yet unused parts. Which then bakes in the ABI that those fields can never be used for anything else but garbage." It's important to ensure that reserved fields are set to known value, so that it will be possible to use them latter to extend the ABI. The same reasonning apply to comp_mask field present in newer uverbs command: per commit 22878dbc9173 ("IB/core: Better checking of userspace values for receive flow steering"), unsupported values in comp_mask are rejected. [1] http://blog.ffwll.ch/2013/11/botching-up-ioctls.html Link: http://marc.info/?i=cover.1386798254.git.ydroneaud@opteya.com> Signed-off-by: Yann Droneaud <ydroneaud@opteya.com> Signed-off-by: Roland Dreier <roland@purestorage.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/infiniband/core/uverbs_main.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 699463bbfd2d..ac2305d8d7c4 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -668,6 +668,9 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
if ((hdr.in_words + ex_hdr.provider_in_words) * 8 != count)
return -EINVAL;
+ if (ex_hdr.cmd_hdr_reserved)
+ return -EINVAL;
+
if (ex_hdr.response) {
if (!hdr.out_words && !ex_hdr.provider_out_words)
return -EINVAL;