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

Pull bpf fixes from Alexei Starovoitov:

 - Fix kCFI failures in JITed BPF code on arm64 (Sami Tolvanen, Puranjay
   Mohan, Mark Rutland, Maxwell Bland)

 - Disallow tail calls between BPF programs that use different cgroup
   local storage maps to prevent out-of-bounds access (Daniel Borkmann)

 - Fix unaligned access in flow_dissector and netfilter BPF programs
   (Paul Chaignon)

 - Avoid possible use of uninitialized mod_len in libbpf (Achill
   Gilgenast)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: Test for unaligned flow_dissector ctx access
  bpf: Improve ctx access verifier error message
  bpf: Check netfilter ctx accesses are aligned
  bpf: Check flow_dissector ctx accesses are aligned
  arm64/cfi,bpf: Support kCFI + BPF on arm64
  cfi: Move BPF CFI types and helpers to generic code
  cfi: add C CFI type macro
  libbpf: Avoid possible use of uninitialized mod_len
  bpf: Fix oob access in cgroup local storage
  bpf: Move cgroup iterator helpers to bpf.h
  bpf: Move bpf map owner out of common struct
  bpf: Add cookie object to bpf maps

1 files changed, 39 insertions, 8 deletions

diff --git a/include/linux/cfi.h b/include/linux/cfi.h
index 1db17ecbb86c..52a98886a455 100644
--- a/include/linux/cfi.h
+++ b/include/linux/cfi.h
@@ -11,16 +11,9 @@
 #include <linux/module.h>
 #include <asm/cfi.h>
 
+#ifdef CONFIG_CFI_CLANG
 extern bool cfi_warn;
 
-#ifndef cfi_get_offset
-static inline int cfi_get_offset(void)
-{
-	return 0;
-}
-#endif
-
-#ifdef CONFIG_CFI_CLANG
 enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr,
 				      unsigned long *target, u32 type);
 
@@ -29,6 +22,44 @@ static inline enum bug_trap_type report_cfi_failure_noaddr(struct pt_regs *regs,
 {
 	return report_cfi_failure(regs, addr, NULL, 0);
 }
+
+#ifndef cfi_get_offset
+/*
+ * Returns the CFI prefix offset. By default, the compiler emits only
+ * a 4-byte CFI type hash before the function. If an architecture
+ * uses -fpatchable-function-entry=N,M where M>0 to change the prefix
+ * offset, they must override this function.
+ */
+static inline int cfi_get_offset(void)
+{
+	return 4;
+}
+#endif
+
+#ifndef cfi_get_func_hash
+static inline u32 cfi_get_func_hash(void *func)
+{
+	u32 hash;
+
+	if (get_kernel_nofault(hash, func - cfi_get_offset()))
+		return 0;
+
+	return hash;
+}
+#endif
+
+/* CFI type hashes for BPF function types */
+extern u32 cfi_bpf_hash;
+extern u32 cfi_bpf_subprog_hash;
+
+#else /* CONFIG_CFI_CLANG */
+
+static inline int cfi_get_offset(void) { return 0; }
+static inline u32 cfi_get_func_hash(void *func) { return 0; }
+
+#define cfi_bpf_hash 0U
+#define cfi_bpf_subprog_hash 0U
+
 #endif /* CONFIG_CFI_CLANG */
 
 #ifdef CONFIG_ARCH_USES_CFI_TRAPS