lkml.org 
[lkml]   [2020]   [Jul]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[Linux-kernel-mentees] [PATCH v2] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id()
    Date
    Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux`
    as NULL. This patch fixes the following syzbot bug:

    https://syzkaller.appspot.com/bug?id=5edd146856fd513747c1992442732e5a0e9ba355

    Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com
    Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
    ---
    Thank you for reviewing my patch! I am new to Linux kernel development; would
    the log message and errno be appropriate for this case?

    Change in v2:
    - Split NULL and IS_ERR cases.

    kernel/bpf/btf.c | 5 +++++
    1 file changed, 5 insertions(+)

    diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
    index 30721f2c2d10..092116a311f4 100644
    --- a/kernel/bpf/btf.c
    +++ b/kernel/bpf/btf.c
    @@ -4088,6 +4088,11 @@ static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn,
    const char *tname, *sym;
    u32 btf_id, i;

    + if (!btf_vmlinux) {
    + bpf_log(log, "btf_vmlinux doesn't exist\n");
    + return -EINVAL;
    + }
    +
    if (IS_ERR(btf_vmlinux)) {
    bpf_log(log, "btf_vmlinux is malformed\n");
    return -EINVAL;
    --
    2.25.1
    \
     
     \ /
      Last update: 2020-07-14 03:29    [W:3.273 / U:0.864 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site