Minimal support for execveat(AT_FDCWD)

termux/proot-distro#299
bjia56 · May 13, 2023 · 2d7c70e · 2d7c70e
1 parent f30ce3e
commit 2d7c70e
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Showing 2 changed files with 16 additions and 0 deletions.
diff --git a/src/syscall/enter.c b/src/syscall/enter.c
@@ -30,6 +30,7 @@
 #include <sys/prctl.h>   /* PR_SET_DUMPABLE */
 #include <termios.h>     /* TCSETS, TCSANOW */
 
+#include "cli/note.h"
 #include "syscall/syscall.h"
 #include "syscall/sysnum.h"
 #include "syscall/socket.h"
@@ -127,6 +128,20 @@ int translate_syscall_enter(Tracee *tracee)
 		status = translate_execve_enter(tracee);
 		break;
 
+	case PR_execveat:
+		if ((int) peek_reg(tracee, CURRENT, SYSARG_1) == AT_FDCWD) {
+			set_sysnum(tracee, PR_execve);
+			poke_reg(tracee, SYSARG_1, peek_reg(tracee, CURRENT, SYSARG_2));
+			poke_reg(tracee, SYSARG_2, peek_reg(tracee, CURRENT, SYSARG_3));
+			poke_reg(tracee, SYSARG_3, peek_reg(tracee, CURRENT, SYSARG_4));
+		} else {
+			note(tracee, ERROR, SYSTEM, "execveat() with non-AT_FDCWD fd is not currently supported");
+			status = -ENOSYS;
+			break;
+		}
+		status = translate_execve_enter(tracee);
+		break;
+
 	case PR_ptrace:
 		status = translate_ptrace_enter(tracee);
 		break;

diff --git a/src/syscall/seccomp.c b/src/syscall/seccomp.c
@@ -343,6 +343,7 @@ static FilteredSysnum proot_sysnums[] = {
 	{ PR_connect,		0 },
 	{ PR_creat,		0 },
 	{ PR_execve,		FILTER_SYSEXIT },
+	{ PR_execveat,		0 },
 	{ PR_faccessat,		0 },
 	{ PR_faccessat2,	0 },
 	{ PR_fchdir,		FILTER_SYSEXIT },