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ppp: fix out-of-bounds access in bpf_prog_create() 

sock_fprog_kern::len is in units of struct sock_filter, not bytes.

Fixes: 3e859adf36 ("compat_ioctl: unify copy-in of ppp filters")
Reported-by: syzbot+eb853b51b10f1befa0b7@syzkaller.appspotmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Biggers 2019-12-04 21:54:19 -08:00 committed by David S. Miller
parent a116f4e238
commit 0033b34a03
1 changed files with 3 additions and 2 deletions
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5
drivers/net/ppp/ppp_generic.c
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@ -564,8 +564,9 @@ static struct bpf_prog *get_filter(struct sock_fprog *uprog)
return NULL;
/* uprog->len is unsigned short, so no overflow here */
fprog.len = uprog->len * sizeof(struct sock_filter);
fprog.filter = memdup_user(uprog->filter, fprog.len);
fprog.len = uprog->len;
fprog.filter = memdup_user(uprog->filter,
uprog->len * sizeof(struct sock_filter));
if (IS_ERR(fprog.filter))
return ERR_CAST(fprog.filter);