kernel: Fix compatibility with old and 32bit programs

In v0.9.3 and v0.9.4, we replaced `vfs_statx` and `do_execveat_common` with syscall hooks. But we missed `fstatat64` and `compat_execve` and break compatibility with old and 32bit programs. In NetHunter Terminal compat_execve is directly called, but `fstatat64` is called before it in JuiceSSH bash-4.2. So add these two hooks back to fix them. Signed-off-by: hamjin <[email protected]>
tiann · Sep 21, 2024 · 5fb13c1 · 5fb13c1
1 parent ac20b76
commit 5fb13c1
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diff --git a/kernel/arch.h b/kernel/arch.h
@@ -21,8 +21,10 @@
 #define PRCTL_SYMBOL "__arm64_sys_prctl"
 #define SYS_READ_SYMBOL "__arm64_sys_read"
 #define SYS_NEWFSTATAT_SYMBOL "__arm64_sys_newfstatat"
+#define SYS_FSTATAT64_SYMBOL "__arm64_sys_fstatat64"
 #define SYS_FACCESSAT_SYMBOL "__arm64_sys_faccessat"
 #define SYS_EXECVE_SYMBOL "__arm64_sys_execve"
+#define SYS_EXECVE_COMPAT_SYMBOL "__arm64_compat_sys_execve"
 
 #elif defined(__x86_64__)
 
@@ -42,8 +44,10 @@
 #define PRCTL_SYMBOL "__x64_sys_prctl"
 #define SYS_READ_SYMBOL "__x64_sys_read"
 #define SYS_NEWFSTATAT_SYMBOL "__x64_sys_newfstatat"
+#define SYS_FSTATAT64_SYMBOL "__x64_sys_fstatat64"
 #define SYS_FACCESSAT_SYMBOL "__x64_sys_faccessat"
 #define SYS_EXECVE_SYMBOL "__x64_sys_execve"
+#define SYS_EXECVE_COMPAT_SYMBOL "__x64_compat_sys_execve"
 
 #else
 #error "Unsupported arch"

diff --git a/kernel/sucompat.c b/kernel/sucompat.c
@@ -232,11 +232,21 @@ static struct kprobe newfstatat_kp = {
 	.pre_handler = sys_newfstatat_handler_pre,
 };
 
+static struct kprobe fstatat64_kp = {
+	.symbol_name = SYS_FSTATAT64_SYMBOL,
+	.pre_handler = sys_newfstatat_handler_pre,
+};
+
 static struct kprobe execve_kp = {
 	.symbol_name = SYS_EXECVE_SYMBOL,
 	.pre_handler = sys_execve_handler_pre,
 };
 
+static struct kprobe execve_compat_kp = {
+	.symbol_name = SYS_EXECVE_COMPAT_SYMBOL,
+	.pre_handler = sys_execve_handler_pre,
+};
+
 static int pts_unix98_lookup_pre(struct kprobe *p, struct pt_regs *regs)
 {
 	struct inode *inode;
@@ -260,8 +270,12 @@ void ksu_sucompat_init()
 	int ret;
 	ret = register_kprobe(&execve_kp);
 	pr_info("sucompat: execve_kp: %d\n", ret);
+	ret = register_kprobe(&execve_compat_kp);
+	pr_info("sucompat: execve_kp: %d\n", ret);
 	ret = register_kprobe(&newfstatat_kp);
 	pr_info("sucompat: newfstatat_kp: %d\n", ret);
+	ret = register_kprobe(&fstatat64_kp);
+	pr_info("sucompat: fstatat64_kp: %d\n", ret);
 	ret = register_kprobe(&faccessat_kp);
 	pr_info("sucompat: faccessat_kp: %d\n", ret);
 	ret = register_kprobe(&pts_unix98_lookup_kp);
@@ -273,7 +287,9 @@ void ksu_sucompat_exit()
 {
 #ifdef CONFIG_KPROBES
 	unregister_kprobe(&execve_kp);
+	unregister_kprobe(&execve_compat_kp);
 	unregister_kprobe(&newfstatat_kp);
+	unregister_kprobe(&fstatat64_kp);
 	unregister_kprobe(&faccessat_kp);
 	unregister_kprobe(&pts_unix98_lookup_kp);
 #endif