Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Pull bpf fixes from Daniel Borkmann:

 - Fix an out-of-bounds read in bpf_link_show_fdinfo for BPF sockmap
   link file descriptors (Hou Tao)

 - Fix BPF arm64 JIT's address emission with tag-based KASAN enabled
   reserving not enough size (Peter Collingbourne)

 - Fix BPF verifier do_misc_fixups patching for inlining of the
   bpf_get_branch_snapshot BPF helper (Andrii Nakryiko)

 - Fix a BPF verifier bug and reject BPF program write attempts into
   read-only marked BPF maps (Daniel Borkmann)

 - Fix perf_event_detach_bpf_prog error handling by removing an invalid
   check which would skip BPF program release (Jiri Olsa)

 - Fix memory leak when parsing mount options for the BPF filesystem
   (Hou Tao)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf: Check validity of link->type in bpf_link_show_fdinfo()
  bpf: Add the missing BPF_LINK_TYPE invocation for sockmap
  bpf: fix do_misc_fixups() for bpf_get_branch_snapshot()
  bpf,perf: Fix perf_event_detach_bpf_prog error handling
  selftests/bpf: Add test for passing in uninit mtu_len
  selftests/bpf: Add test for writes to .rodata
  bpf: Remove MEM_UNINIT from skb/xdp MTU helpers
  bpf: Fix overloading of MEM_UNINIT's meaning
  bpf: Add MEM_WRITE attribute
  bpf: Preserve param->string when parsing mount options
  bpf, arm64: Fix address emission with tag-based KASAN enabled

1 files changed, 11 insertions, 3 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 19d8ca8ac960..bdadb0bb6cec 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -635,6 +635,7 @@ enum bpf_type_flag {
 	 */
 	PTR_UNTRUSTED		= BIT(6 + BPF_BASE_TYPE_BITS),
 
+	/* MEM can be uninitialized. */
 	MEM_UNINIT		= BIT(7 + BPF_BASE_TYPE_BITS),
 
 	/* DYNPTR points to memory local to the bpf program. */
@@ -700,6 +701,13 @@ enum bpf_type_flag {
 	 */
 	MEM_ALIGNED		= BIT(17 + BPF_BASE_TYPE_BITS),
 
+	/* MEM is being written to, often combined with MEM_UNINIT. Non-presence
+	 * of MEM_WRITE means that MEM is only being read. MEM_WRITE without the
+	 * MEM_UNINIT means that memory needs to be initialized since it is also
+	 * read.
+	 */
+	MEM_WRITE		= BIT(18 + BPF_BASE_TYPE_BITS),
+
 	__BPF_TYPE_FLAG_MAX,
 	__BPF_TYPE_LAST_FLAG	= __BPF_TYPE_FLAG_MAX - 1,
 };
@@ -758,10 +766,10 @@ enum bpf_arg_type {
 	ARG_PTR_TO_SOCKET_OR_NULL	= PTR_MAYBE_NULL | ARG_PTR_TO_SOCKET,
 	ARG_PTR_TO_STACK_OR_NULL	= PTR_MAYBE_NULL | ARG_PTR_TO_STACK,
 	ARG_PTR_TO_BTF_ID_OR_NULL	= PTR_MAYBE_NULL | ARG_PTR_TO_BTF_ID,
-	/* pointer to memory does not need to be initialized, helper function must fill
-	 * all bytes or clear them in error case.
+	/* Pointer to memory does not need to be initialized, since helper function
+	 * fills all bytes or clears them in error case.
 	 */
-	ARG_PTR_TO_UNINIT_MEM		= MEM_UNINIT | ARG_PTR_TO_MEM,
+	ARG_PTR_TO_UNINIT_MEM		= MEM_UNINIT | MEM_WRITE | ARG_PTR_TO_MEM,
 	/* Pointer to valid memory of size known at compile time. */
 	ARG_PTR_TO_FIXED_SIZE_MEM	= MEM_FIXED_SIZE | ARG_PTR_TO_MEM,