selinux: fall back to ref-walk if audit is required

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commit 0188d5c025 upstream.

commit bda0be7ad9 ("security: make inode_follow_link RCU-walk aware")
passed down the rcu flag to the SELinux AVC, but failed to adjust the
test in slow_avc_audit() to also return -ECHILD on LSM_AUDIT_DATA_DENTRY.
Previously, we only returned -ECHILD if generating an audit record with
LSM_AUDIT_DATA_INODE since this was only relevant from inode_permission.
Move the handling of MAY_NOT_BLOCK to avc_audit() and its inlined
equivalent in selinux_inode_permission() immediately after we determine
that audit is required, and always fall back to ref-walk in this case.

Fixes: bda0be7ad9 ("security: make inode_follow_link RCU-walk aware")
Reported-by: Will Deacon <will@kernel.org>
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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This commit is contained in:

Stephen Smalley 2019-11-22 12:22:45 -05:00 • committed by Greg Kroah-Hartman

parent 36f4415181

commit 2c83164bf1

3 changed files with 17 additions and 26 deletions

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24

security/selinux/avc.c

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11

security/selinux/hooks.c

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8

security/selinux/include/avc.h

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