JIRA: https://issues.redhat.com/browse/RHEL-33903
commit ac13a4261afe81ca423eddd8e6571078fe2a7cea
Author: Song Liu <song@kernel.org>
Date: Tue Aug 6 16:09:03 2024 -0700
bpf: Add kfunc bpf_get_dentry_xattr() to read xattr from dentry
This kfunc can be used in LSM hooks with dentry, such as:
security_inode_listxattr
security_inode_permission
and many more.
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240806230904.71194-3-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Gregory Bell <grbell@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-33903
Conflicts: Incorporates changes to bpf_get_file_xattr
omitted from b41752a1a7 ("bpf: treewide: Align kfunc signatures to prog point-of-view")
commit fa4e5afa9758e6567a6a54ea7bf53d570ec94881
Author: Song Liu <song@kernel.org>
Date: Tue Aug 6 16:09:02 2024 -0700
bpf: Move bpf_get_file_xattr to fs/bpf_fs_kfuncs.c
We are putting all fs kfuncs in fs/bpf_fs_kfuncs.c. Move existing
bpf_get_file_xattr to it.
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240806230904.71194-2-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Gregory Bell <grbell@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-63880
commit d08e2045ebf0f5f2a97ad22cc7dae398b35354ba
Author: Matt Bobrowski <mattbobrowski@google.com>
Date: Wed Jul 31 11:08:31 2024 +0000
bpf: introduce new VFS based BPF kfuncs
Add a new variant of bpf_d_path() named bpf_path_d_path() which takes
the form of a BPF kfunc and enforces KF_TRUSTED_ARGS semantics onto
its arguments.
This new d_path() based BPF kfunc variant is intended to address the
legacy bpf_d_path() BPF helper's susceptability to memory corruption
issues [0, 1, 2] by ensuring to only operate on supplied arguments
which are deemed trusted by the BPF verifier. Typically, this means
that only pointers to a struct path which have been referenced counted
may be supplied.
In addition to the new bpf_path_d_path() BPF kfunc, we also add a
KF_ACQUIRE based BPF kfunc bpf_get_task_exe_file() and KF_RELEASE
counterpart BPF kfunc bpf_put_file(). This is so that the new
bpf_path_d_path() BPF kfunc can be used more flexibily from within the
context of a BPF LSM program. It's rather common to ascertain the
backing executable file for the calling process by performing the
following walk current->mm->exe_file while instrumenting a given
operation from the context of the BPF LSM program. However, walking
current->mm->exe_file directly is never deemed to be OK, and doing so
from both inside and outside of BPF LSM program context should be
considered as a bug. Using bpf_get_task_exe_file() and in turn
bpf_put_file() will allow BPF LSM programs to reliably get and put
references to current->mm->exe_file.
As of now, all the newly introduced BPF kfuncs within this patch are
limited to BPF LSM program types. These can be either sleepable or
non-sleepable variants of BPF LSM program types.
[0] https://lore.kernel.org/bpf/CAG48ez0ppjcT=QxU-jtCUfb5xQb3mLr=5FcwddF_VKfEBPs_Dg@mail.gmail.com/
[1] https://lore.kernel.org/bpf/20230606181714.532998-1-jolsa@kernel.org/
[2] https://lore.kernel.org/bpf/20220219113744.1852259-1-memxor@gmail.com/
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240731110833.1834742-2-mattbobrowski@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Gregory Bell
Jerome Marchand