WEBDIENSTE/unbound
1
0
Fork 0
mirror of https://github.com/NLnetLabs/unbound.git synced 2026-09-26 19:54:53 +02:00
Code Issues Packages Projects Releases Wiki Activity

Ensure proper alignment of cmsg buffers

Browse Source 
The cmsg macros expect a control message buffer to be aligned like
a struct cmsghdr.  The current layout around those stack-allocated
buffers probably provides the required alignment (usually 4 bytes).
Use a union to enforce proper alignment, in case future changes modify
the stack layout.

Spotted when chasing an unrelated bug with Otto Moerbeek (@omoerbeek).
This commit is contained in:
Jeremie Courreges-Anglas
2020-05-10 17:23:33 +02:00
parent a269db3828
commit 8175161059
1 changed files with 12 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files
util/netevent.c
+12 -6
View File
@@ -447,7 +447,10 @@ comm_point_send_udp_msg_if(struct comm_point *c, sldns_buffer* packet,
ssize_t sent;
struct msghdr msg;
struct iovec iov[1];
char control[256];
union {
struct cmsghdr hdr;
char buf[256];
} control;
#ifndef S_SPLINT_S
struct cmsghdr *cmsg;
#endif /* S_SPLINT_S */
@@ -465,9 +468,9 @@ comm_point_send_udp_msg_if(struct comm_point *c, sldns_buffer* packet,
iov[0].iov_len = sldns_buffer_remaining(packet);
msg.msg_iov = iov;
msg.msg_iovlen = 1;
msg.msg_control = control;
msg.msg_control = control.buf;
#ifndef S_SPLINT_S
msg.msg_controllen = sizeof(control);
msg.msg_controllen = sizeof(control.buf);
#endif /* S_SPLINT_S */
msg.msg_flags = 0;
@@ -584,7 +587,10 @@ comm_point_udp_ancil_callback(int fd, short event, void* arg)
struct msghdr msg;
struct iovec iov[1];
ssize_t rcv;
char ancil[256];
union {
struct cmsghdr hdr;
char buf[256];
} ancil;
int i;
#ifndef S_SPLINT_S
struct cmsghdr* cmsg;
@@ -608,9 +614,9 @@ comm_point_udp_ancil_callback(int fd, short event, void* arg)
iov[0].iov_len = sldns_buffer_remaining(rep.c->buffer);
msg.msg_iov = iov;
msg.msg_iovlen = 1;
msg.msg_control = ancil;
msg.msg_control = ancil.buf;
#ifndef S_SPLINT_S
msg.msg_controllen = sizeof(ancil);
msg.msg_controllen = sizeof(ancil.buf);
#endif /* S_SPLINT_S */
msg.msg_flags = 0;
rcv = recvmsg(fd, &msg, 0);