AX.25: Fix out-of-bounds read in ax25_connect()
[ Upstream commit 2f2a7ffad5
]
Checks on `addr_len` and `fsa->fsa_ax25.sax25_ndigis` are insufficient.
ax25_connect() can go out of bounds when `fsa->fsa_ax25.sax25_ndigis`
equals to 7 or 8. Fix it.
This issue has been reported as a KMSAN uninit-value bug, because in such
a case, ax25_connect() reaches into the uninitialized portion of the
`struct sockaddr_storage` statically allocated in __sys_connect().
It is safe to remove `fsa->fsa_ax25.sax25_ndigis > AX25_MAX_DIGIS` because
`addr_len` is guaranteed to be less than or equal to
`sizeof(struct full_sockaddr_ax25)`.
Reported-by: syzbot+c82752228ed975b0a623@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=55ef9d629f3b3d7d70b69558015b63b48d01af66
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
58a12e3368
commit
2f1624faf6
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@ -1187,7 +1187,9 @@ static int __must_check ax25_connect(struct socket *sock,
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if (addr_len > sizeof(struct sockaddr_ax25) &&
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fsa->fsa_ax25.sax25_ndigis != 0) {
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/* Valid number of digipeaters ? */
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if (fsa->fsa_ax25.sax25_ndigis < 1 || fsa->fsa_ax25.sax25_ndigis > AX25_MAX_DIGIS) {
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if (fsa->fsa_ax25.sax25_ndigis < 1 ||
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addr_len < sizeof(struct sockaddr_ax25) +
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sizeof(ax25_address) * fsa->fsa_ax25.sax25_ndigis) {
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err = -EINVAL;
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goto out_release;
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}
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