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| author | Matthew Wilcox <willy@infradead.org> | 2020-10-15 20:13:08 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-16 11:11:22 -0700 |
| commit | 589f6b52682542c1b230c435e1de679755f3332a (patch) | |
| tree | 701c254c643a11e7f2f3dc2b252d4d0902d0cf36 /fs/autofs | |
| parent | 50b7d85680086126d7bd91dae81d57d4cb1ab6b7 (diff) | |
| download | lwn-589f6b52682542c1b230c435e1de679755f3332a.tar.gz lwn-589f6b52682542c1b230c435e1de679755f3332a.zip | |
autofs: harden ioctl table
The table of ioctl functions should be marked const in order to put them
in read-only memory, and we should use array_index_nospec() to avoid
speculation disclosing the contents of kernel memory to userspace.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Ian Kent <raven@themaw.net>
Link: https://lkml.kernel.org/r/20200818122203.GO17456@casper.infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/autofs')
| -rw-r--r-- | fs/autofs/dev-ioctl.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c index 75105f45c51a..322b7dfb4ea0 100644 --- a/fs/autofs/dev-ioctl.c +++ b/fs/autofs/dev-ioctl.c @@ -8,6 +8,7 @@ #include <linux/compat.h> #include <linux/syscalls.h> #include <linux/magic.h> +#include <linux/nospec.h> #include "autofs_i.h" @@ -563,7 +564,7 @@ out: static ioctl_fn lookup_dev_ioctl(unsigned int cmd) { - static ioctl_fn _ioctls[] = { + static const ioctl_fn _ioctls[] = { autofs_dev_ioctl_version, autofs_dev_ioctl_protover, autofs_dev_ioctl_protosubver, @@ -581,7 +582,10 @@ static ioctl_fn lookup_dev_ioctl(unsigned int cmd) }; unsigned int idx = cmd_idx(cmd); - return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx]; + if (idx >= ARRAY_SIZE(_ioctls)) + return NULL; + idx = array_index_nospec(idx, ARRAY_SIZE(_ioctls)); + return _ioctls[idx]; } /* ioctl dispatcher */ |