55 lines
2.6 KiB
Diff
55 lines
2.6 KiB
Diff
From 011880f527ff317a40769ea8673a6353e5db53ac Mon Sep 17 00:00:00 2001
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From: Prasad J Pandit <pjp@fedoraproject.org>
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Date: Tue, 14 Apr 2020 18:23:23 +0800
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Subject: [PATCH] slirp: use correct size while emulating IRC commands
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While emulating IRC DCC commands, tcp_emu() uses 'mbuf' size
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'm->m_size' to write DCC commands via snprintf(3). This may
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lead to OOB write access, because 'bptr' points somewhere in
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the middle of 'mbuf' buffer, not at the start. Use M_FREEROOM(m)
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size to avoid OOB access.
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Reported-by: default avatarVishnu Dev TJ <vishnudevtj@gmail.com>
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Signed-off-by: default avatarPrasad J Pandit <pjp@fedoraproject.org>
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Reviewed-by: Samuel Thibault's avatarSamuel Thibault <samuel.thibault@ens-lyon.org>
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Message-Id: <20200109094228.79764-2-ppandit@redhat.com>
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---
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slirp/src/tcp_subr.c | 9 ++++++---
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1 file changed, 6 insertions(+), 3 deletions(-)
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diff --git a/slirp/src/tcp_subr.c b/slirp/src/tcp_subr.c
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index 9c94c03a..2a15b16a 100644
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--- a/slirp/src/tcp_subr.c
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+++ b/slirp/src/tcp_subr.c
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@@ -778,7 +778,8 @@ int tcp_emu(struct socket *so, struct mbuf *m)
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return 1;
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}
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m->m_len = bptr - m->m_data; /* Adjust length */
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- m->m_len += snprintf(bptr, m->m_size, "DCC CHAT chat %lu %u%c\n",
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+ m->m_len += snprintf(bptr, M_FREEROOM(m),
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+ "DCC CHAT chat %lu %u%c\n",
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(unsigned long)ntohl(so->so_faddr.s_addr),
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ntohs(so->so_fport), 1);
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} else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport,
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@@ -789,7 +790,8 @@ int tcp_emu(struct socket *so, struct mbuf *m)
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}
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m->m_len = bptr - m->m_data; /* Adjust length */
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m->m_len +=
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- snprintf(bptr, m->m_size, "DCC SEND %s %lu %u %u%c\n", buff,
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+ snprintf(bptr, M_FREEROOM(m),
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+ "DCC SEND %s %lu %u %u%c\n", buff,
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(unsigned long)ntohl(so->so_faddr.s_addr),
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ntohs(so->so_fport), n1, 1);
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} else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport,
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@@ -800,7 +802,8 @@ int tcp_emu(struct socket *so, struct mbuf *m)
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}
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m->m_len = bptr - m->m_data; /* Adjust length */
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m->m_len +=
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- snprintf(bptr, m->m_size, "DCC MOVE %s %lu %u %u%c\n", buff,
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+ snprintf(bptr, M_FREEROOM(m),
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+ "DCC MOVE %s %lu %u %u%c\n", buff,
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(unsigned long)ntohl(so->so_faddr.s_addr),
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ntohs(so->so_fport), n1, 1);
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}
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--
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2.23.0
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