lkml.org 
[lkml]   [2018]   [Dec]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] bpf: fix missing checks of the return value of check_reg_arg
Date
check_reg_arg() may fail. This fix inserts checks for its return value.
If check_reg_arg() fails, issues an error message.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
kernel/bpf/verifier.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 51ba84d4d34a..fde91a5c0b5a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2619,7 +2619,10 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
/* after the call registers r0 - r5 were scratched */
for (i = 0; i < CALLER_SAVED_REGS; i++) {
mark_reg_not_init(env, caller->regs, caller_saved[i]);
- check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+ err = check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+ if (err)
+ verbose(env,
+ "check_reg_arg() fails in setting caller saved regs\n");
}

/* only increment it after check_reg_arg() finished */
@@ -2842,7 +2845,10 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
/* reset caller saved regs */
for (i = 0; i < CALLER_SAVED_REGS; i++) {
mark_reg_not_init(env, regs, caller_saved[i]);
- check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+ err = check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+ if (err)
+ verbose(env,
+ "check_reg_arg() fails in resetting caller saved regs\n");
}

/* update return register (already marked as written above) */
@@ -4435,7 +4441,10 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
/* reset caller saved regs to unreadable */
for (i = 0; i < CALLER_SAVED_REGS; i++) {
mark_reg_not_init(env, regs, caller_saved[i]);
- check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+ err = check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+ if (err)
+ verbose(env,
+ "check_reg_arg() fails in resetting caller saved regs to unreadable\n");
}

/* mark destination R0 register as readable, since it contains
--
2.17.2 (Apple Git-113)
\
 
 \ /
  Last update: 2018-12-25 08:18    [W:0.036 / U:0.080 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site