Messages in this thread | | | From | Stephen Smalley <> | Date | Wed, 6 Sep 2023 13:49:14 -0400 | Subject | Re: [PATCH V2] SELinux: Check correct permissions for FS_IOC32_* |
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On Wed, Sep 6, 2023 at 7:59 AM Alfred Piccioni <alpic@google.com> wrote: > > Some ioctl commands do not require ioctl permission, but are routed to > other permissions such as FILE_GETATTR or FILE_SETATTR. This routing is > done by comparing the ioctl cmd to a set of 64-bit flags (FS_IOC_*). > > However, if a 32-bit process is running on a 64-bit kernel, it emits > 32-bit flags (FS_IOC32_*) for certain ioctl operations. These flags are > being checked erroneously, which leads to these ioctl operations being > routed to the ioctl permission, rather than the correct file permissions. > > Two possible solutions exist: > > - Trim parameter "cmd" to a u16 so that only the last two bytes are > checked in the case statement. > > - Explicitly add the FS_IOC32_* codes to the case statement. > > Solution 2 was chosen because it is a minimal explicit change. Solution > 1 is a more elegant change, but is less explicit, as the switch > statement appears to only check the FS_IOC_* codes upon first reading. > > Fixes: 0b24dcb7f2f7 ("Revert "selinux: simplify ioctl checking"") > Signed-off-by: Alfred Piccioni <alpic@google.com> > Cc: stable@vger.kernel.org
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
> --- > V1->V2: Cleaned up some typos and added tag for -stable tree inclusion. > > security/selinux/hooks.c | 4 ++++ > 1 file changed, 4 insertions(+)
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