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Fix `recvmsg`/`sendmsg` alignment issues
Fixes #761
Linux CMSGs are aligned to 8 bytes, but BSD CMSgs are aligned to 4 bytes.
We were correctly adding 4 to the length of BSD message to account for the extra 4 bytes in the message length field, but we were still aligning the data to 4 bytes. This fixes that by aligning to 8 bytes instead.
+22
-9
+6
-5
src/kernel/emulation/linux/network/recvmsg.c
+6
-5
src/kernel/emulation/linux/network/recvmsg.c
···
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else if (msg->msg_control != NULL && msg->msg_controllen > 0)
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{
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// __simple_printf("controllen=%d\n", msg->msg_controllen);
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-
lchdr = (struct linux_cmsghdr*) malloc(msg->msg_controllen + 4);
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lmsg.msg_controllen = LINUX_CMSG_ALIGN(msg->msg_controllen + LINUX_BSD_CMSGHDR_SIZE_DIFFERENCE); // FIXME: there could be multiple control messages in a message
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lchdr = (struct linux_cmsghdr*) malloc(lmsg.msg_controllen);
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lmsg.msg_control = lchdr;
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lmsg.msg_controllen = msg->msg_controllen + 4; // FIXME: there could be multiple control messages in a message
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}
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else
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{
···
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// __simple_printf("Linux msg at %d -> BSD at %d\n", lpos, bpos);
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-
bnext->cmsg_len = lnext->cmsg_len - (sizeof(struct linux_cmsghdr) - sizeof(struct bsd_cmsghdr));
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bnext->cmsg_len = lnext->cmsg_len - LINUX_BSD_CMSGHDR_SIZE_DIFFERENCE;
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bnext->cmsg_level = socket_level_linux_to_bsd(lnext->cmsg_level);
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bnext->cmsg_type = lnext->cmsg_type;
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// __simple_printf("About to copy %d bytes\n", lnext->cmsg_len - sizeof(struct linux_cmsghdr));
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memcpy(bnext->cmsg_data, lnext->cmsg_data, lnext->cmsg_len - sizeof(struct linux_cmsghdr));
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-
msg->msg_controllen -= 4;
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size_t actual_data_size = lnext->cmsg_len - sizeof(struct linux_cmsghdr);
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memcpy(bnext->cmsg_data, lnext->cmsg_data, actual_data_size);
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msg->msg_controllen -= LINUX_CMSG_SPACE(actual_data_size) - BSD_CMSG_SPACE(actual_data_size);
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lpos += ALIGN(lnext->cmsg_len, sizeof(unsigned long));
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bpos += ALIGN(bnext->cmsg_len, 4);
+10
src/kernel/emulation/linux/network/recvmsg.h
+10
src/kernel/emulation/linux/network/recvmsg.h
···
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#define LINUX_SYS_RECVMSG 17
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#define BSD_CMSG_ALIGN(len) (((len) + sizeof(uint32_t) - 1) & (size_t)~(sizeof(uint32_t) - 1))
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#define BSD_CMSG_SPACE(len) (BSD_CMSG_ALIGN(sizeof(struct bsd_cmsghdr)) + BSD_CMSG_ALIGN(len))
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#define BSD_CMSG_LEN(len) (BSD_CMSG_ALIGN(sizeof(struct bsd_cmsghdr)) + (len))
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+
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#define LINUX_CMSG_ALIGN(len) (((len) + sizeof(unsigned long) - 1) & (size_t)~(sizeof(unsigned long) - 1))
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#define LINUX_CMSG_SPACE(len) (LINUX_CMSG_ALIGN(sizeof(struct linux_cmsghdr)) + LINUX_CMSG_ALIGN(len))
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#define LINUX_CMSG_LEN(len) (LINUX_CMSG_ALIGN(sizeof(struct linux_cmsghdr)) + (len))
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#define LINUX_BSD_CMSGHDR_SIZE_DIFFERENCE (sizeof(struct linux_cmsghdr) - sizeof(struct bsd_cmsghdr))
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#endif
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+6
-4
src/kernel/emulation/linux/network/sendmsg.c
+6
-4
src/kernel/emulation/linux/network/sendmsg.c
···
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struct bsd_cmsghdr* bchdr;
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bchdr = (struct bsd_cmsghdr*) msg->msg_control;
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lchdr = (struct linux_cmsghdr*) malloc(msg->msg_controllen + 4);
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lmsg.msg_controllen = LINUX_CMSG_ALIGN(msg->msg_controllen + LINUX_BSD_CMSGHDR_SIZE_DIFFERENCE);
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lchdr = (struct linux_cmsghdr*)malloc(lmsg.msg_controllen);
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lmsg.msg_control = lchdr;
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lmsg.msg_controllen = msg->msg_controllen + 4;
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lchdr->cmsg_len = bchdr->cmsg_len;
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lchdr->cmsg_len = bchdr->cmsg_len + LINUX_BSD_CMSGHDR_SIZE_DIFFERENCE;
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lchdr->cmsg_level = socket_level_bsd_to_linux(bchdr->cmsg_level);
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lchdr->cmsg_type = bchdr->cmsg_type;
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memcpy(lchdr->cmsg_data, bchdr->cmsg_data,
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lchdr->cmsg_len - sizeof(struct bsd_cmsghdr));
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bchdr->cmsg_len - sizeof(struct bsd_cmsghdr));
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}
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else
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{