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

Pull bpf fixes from Alexei Starovoitov:

 - Fix overflow of backward jump offset in constant blinding
   (Alexei Starovoitov)

 - Fix packet range of packet pointers sharing an id when var_off
   tightens umax of one pointer and not the other (Alexei Starovoitov)

 - Fix objects stuck in free_by_rcu_ttrace list of bpf memalloc
   (Alexei Starovoitov)

 - Fix use-after-free of progs detached from busy trampolines: wait for
   an RCU tasks grace period before freeing trampoline progs, and patch
   detached progs out of trampoline images that are still in use
   (Florent Revest)

 - Hold map BTF for the memory allocator destructor record to fix UAF in
   deferred bpf_mem_alloc destruction (Kumar Kartikeya Dwivedi)

 - Fix missing migration protection in resizable hashtab
   lookup_and_delete batch operation (Ömer Mete Kaya)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf: Fix missing migration protection in __rhtab_map_lookup_and_delete_batch()
  selftests/bpf: Add a test for objects stuck in free_by_rcu_ttrace
  bpf: Fix objects stuck in free_by_rcu_ttrace
  bpf: Factor out __do_call_rcu_ttrace()
  selftests/bpf: Test packet range of pointers sharing an id
  bpf: Fix packet range of pointers sharing an id
  selftests/bpf: Detach a trampoline prog while a task sleeps before it
  bpf: Skip detached progs in trampoline images that are still in use
  bpf: Wait for an RCU tasks grace period before freeing trampoline progs
  bpf: Hold map BTF for the memory allocator destructor record
  bpf: Fix overflow of jump offset in constant blinding

1 files changed, 22 insertions, 15 deletions

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index c5f55d616..c1279fabc 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -2418,10 +2418,11 @@ bool bpf_jit_supports_subprog_tailcalls(void)
 	return true;
 }
 
-static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_node *node,
-			    int bargs_off, int retval_off, int run_ctx_off,
-			    bool save_ret)
+static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_image *im,
+			    struct bpf_tramp_node *node, int bargs_off,
+			    int retval_off, int run_ctx_off, bool save_ret)
 {
+	void *skip;
 	__le32 *branch;
 	u64 enter_prog;
 	u64 exit_prog;
@@ -2431,6 +2432,10 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_node *node,
 	enter_prog = (u64)bpf_trampoline_enter(p);
 	exit_prog = (u64)bpf_trampoline_exit(p);
 
+	/* nop, patched to skip this prog when it is detached */
+	skip = ctx->ro_image + ctx->idx;
+	emit(A64_NOP, ctx);
+
 	if (node->cookie == 0) {
 		/* if cookie is zero, one instruction is enough to store it */
 		emit(A64_STR64I(A64_ZR, A64_SP, run_ctx_off + cookie_off), ctx);
@@ -2483,11 +2488,13 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_node *node,
 	emit(A64_ADD_I(1, A64_R(2), A64_SP, run_ctx_off), ctx);
 
 	emit_call(exit_prog, ctx);
+
+	bpf_tramp_image_add_skip(im, p, skip, ctx->ro_image + ctx->idx);
 }
 
-static void invoke_bpf_mod_ret(struct jit_ctx *ctx, struct bpf_tramp_nodes *tn,
-			       int bargs_off, int retval_off, int run_ctx_off,
-			       __le32 **branches)
+static void invoke_bpf_mod_ret(struct jit_ctx *ctx, struct bpf_tramp_image *im,
+			       struct bpf_tramp_nodes *tn, int bargs_off,
+			       int retval_off, int run_ctx_off, __le32 **branches)
 {
 	int i;
 
@@ -2496,7 +2503,7 @@ static void invoke_bpf_mod_ret(struct jit_ctx *ctx, struct bpf_tramp_nodes *tn,
 	 */
 	emit(A64_STR64I(A64_ZR, A64_SP, retval_off), ctx);
 	for (i = 0; i < tn->nr_nodes; i++) {
-		invoke_bpf_prog(ctx, tn->nodes[i], bargs_off, retval_off,
+		invoke_bpf_prog(ctx, im, tn->nodes[i], bargs_off, retval_off,
 				run_ctx_off, true);
 		/* if (*(u64 *)(sp + retval_off) !=  0)
 		 *	goto do_fexit;
@@ -2882,7 +2889,7 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im,
 			store_func_meta(ctx, meta, func_meta_off);
 			cookie_bargs_off--;
 		}
-		invoke_bpf_prog(ctx, fentry->nodes[i], bargs_off,
+		invoke_bpf_prog(ctx, im, fentry->nodes[i], bargs_off,
 				retval_off, run_ctx_off,
 				flags & BPF_TRAMP_F_RET_FENTRY_RET);
 	}
@@ -2893,7 +2900,7 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im,
 		if (!branches)
 			return -ENOMEM;
 
-		invoke_bpf_mod_ret(ctx, fmod_ret, bargs_off, retval_off,
+		invoke_bpf_mod_ret(ctx, im, fmod_ret, bargs_off, retval_off,
 				   run_ctx_off, branches);
 	}
 
@@ -2906,9 +2913,6 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im,
 		emit(A64_RET(A64_R(10)), ctx);
 		/* store return value */
 		emit(A64_STR64I(A64_R(0), A64_SP, retval_off), ctx);
-		/* reserve a nop for bpf_tramp_image_put */
-		im->ip_after_call = ctx->ro_image + ctx->idx;
-		emit(A64_NOP, ctx);
 	}
 
 	/* update the branches saved in invoke_bpf_mod_ret with cbnz */
@@ -2930,12 +2934,11 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im,
 			store_func_meta(ctx, meta, func_meta_off);
 			cookie_bargs_off--;
 		}
-		invoke_bpf_prog(ctx, fexit->nodes[i], bargs_off, retval_off,
+		invoke_bpf_prog(ctx, im, fexit->nodes[i], bargs_off, retval_off,
 				run_ctx_off, false);
 	}
 
 	if (flags & BPF_TRAMP_F_CALL_ORIG) {
-		im->ip_epilogue = ctx->ro_image + ctx->idx;
 		/* for the first pass, assume the worst case */
 		if (!ctx->image)
 			ctx->idx += 4;
@@ -2994,7 +2997,7 @@ int arch_bpf_trampoline_size(const struct btf_func_model *m, u32 flags,
 		.image = NULL,
 		.idx = 0,
 	};
-	struct bpf_tramp_image im;
+	struct bpf_tramp_image im = {};
 	struct arg_aux aaux;
 	int ret;
 
@@ -3281,6 +3284,10 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type old_t,
 	 *    longer reachable, since bpf_tramp_image_put() function already
 	 *    uses percpu_ref and task-based rcu to do the sync, no need to call
 	 *    the sync version here, see bpf_tramp_image_put() for details.
+	 *
+	 * 3. when a detached prog is patched out of a trampoline, a CPU that
+	 *    still executes the old nop calls the prog before it went through
+	 *    a quiescent state, and the prog is freed after grace periods.
 	 */
 	ret = aarch64_insn_patch_text_nosync(ip, new_insn);
 out: