From ee1045877a7e226945c7cec2bda80039bd2d0c8e Mon Sep 17 00:00:00 2001 From: Jonathan Neuschäfer Date: Thu, 3 Sep 2015 07:27:26 +0200 Subject: linux-user: fix cmsg conversion in case of multiple headers Currently, __target_cmsg_nxthdr compares a pointer derived from target_cmsg against the msg_control field of target_msgh (through subtraction). This failed for me when emulating i386 code under x86_64, because pointers in the host address space and pointers in the guest address space were not the same. This patch passes the initial value of target_cmsg into __target_cmsg_nxthdr. I found and fixed two more related bugs: - __target_cmsg_nxthdr now returns the new cmsg pointer instead of the old one. - tgt_space (in host_to_target_cmsg) doesn't count "sizeof (struct target_cmsghdr)" twice anymore. Reviewed-by: Peter Maydell Signed-off-by: Jonathan Neuschäfer Signed-off-by: Riku Voipio --- linux-user/syscall_defs.h | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) (limited to 'linux-user/syscall_defs.h') diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h index cdc8db421c..7ca33a6f62 100644 --- a/linux-user/syscall_defs.h +++ b/linux-user/syscall_defs.h @@ -235,7 +235,8 @@ struct target_cmsghdr { }; #define TARGET_CMSG_DATA(cmsg) ((unsigned char *) ((struct target_cmsghdr *) (cmsg) + 1)) -#define TARGET_CMSG_NXTHDR(mhdr, cmsg) __target_cmsg_nxthdr (mhdr, cmsg) +#define TARGET_CMSG_NXTHDR(mhdr, cmsg, cmsg_start) \ + __target_cmsg_nxthdr(mhdr, cmsg, cmsg_start) #define TARGET_CMSG_ALIGN(len) (((len) + sizeof (abi_long) - 1) \ & (size_t) ~(sizeof (abi_long) - 1)) #define TARGET_CMSG_SPACE(len) (TARGET_CMSG_ALIGN (len) \ @@ -243,17 +244,20 @@ struct target_cmsghdr { #define TARGET_CMSG_LEN(len) (TARGET_CMSG_ALIGN (sizeof (struct target_cmsghdr)) + (len)) static __inline__ struct target_cmsghdr * -__target_cmsg_nxthdr (struct target_msghdr *__mhdr, struct target_cmsghdr *__cmsg) +__target_cmsg_nxthdr(struct target_msghdr *__mhdr, + struct target_cmsghdr *__cmsg, + struct target_cmsghdr *__cmsg_start) { struct target_cmsghdr *__ptr; __ptr = (struct target_cmsghdr *)((unsigned char *) __cmsg + TARGET_CMSG_ALIGN (tswapal(__cmsg->cmsg_len))); - if ((unsigned long)((char *)(__ptr+1) - (char *)(size_t)tswapal(__mhdr->msg_control)) - > tswapal(__mhdr->msg_controllen)) + if ((unsigned long)((char *)(__ptr+1) - (char *)__cmsg_start) + > tswapal(__mhdr->msg_controllen)) { /* No more entries. */ return (struct target_cmsghdr *)0; - return __cmsg; + } + return __ptr; } struct target_mmsghdr { -- cgit v1.2.3-55-g7522