MFC r266925:

To allow to run the interpreter itself add a new ELF branding type.
Allow Linux ABI to run ELF interpreter.

4 files changed, 34 insertions, 4 deletions

diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c
index c06ce11..9b5c555 100644
--- a/sys/amd64/linux32/linux32_sysvec.c
+++ b/sys/amd64/linux32/linux32_sysvec.c
@@ -1083,7 +1083,7 @@ static Elf32_Brandinfo linux_brand = {
 	.sysvec		= &elf_linux_sysvec,
 	.interp_newpath	= NULL,
 	.brand_note	= &linux32_brandnote,
-	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
+	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE | BI_CAN_EXEC_INTERP
 };
 
 static Elf32_Brandinfo linux_glibc2brand = {
@@ -1095,7 +1095,7 @@ static Elf32_Brandinfo linux_glibc2brand = {
 	.sysvec		= &elf_linux_sysvec,
 	.interp_newpath	= NULL,
 	.brand_note	= &linux32_brandnote,
-	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
+	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE | BI_CAN_EXEC_INTERP
 };
 
 Elf32_Brandinfo *linux_brandlist[] = {
diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
index 0ad6791..60df6a2 100644
--- a/sys/i386/linux/linux_sysvec.c
+++ b/sys/i386/linux/linux_sysvec.c
@@ -1058,7 +1058,7 @@ static Elf32_Brandinfo linux_brand = {
 	.sysvec		= &elf_linux_sysvec,
 	.interp_newpath	= NULL,
 	.brand_note	= &linux_brandnote,
-	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
+	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE | BI_CAN_EXEC_INTERP 
 };
 
 static Elf32_Brandinfo linux_glibc2brand = {
@@ -1070,7 +1070,7 @@ static Elf32_Brandinfo linux_glibc2brand = {
 	.sysvec		= &elf_linux_sysvec,
 	.interp_newpath	= NULL,
 	.brand_note	= &linux_brandnote,
-	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
+	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE | BI_CAN_EXEC_INTERP 
 };
 
 Elf32_Brandinfo *linux_brandlist[] = {
diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
index 8783670..a9659a1 100644
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -261,6 +261,8 @@ __elfN(get_brandinfo)(struct image_params *imgp, const char *interp,
 {
 	const Elf_Ehdr *hdr = (const Elf_Ehdr *)imgp->image_header;
 	Elf_Brandinfo *bi;
+	const char *fname_name, *interp_brand_name;
+	int fname_len, interp_len;
 	boolean_t ret;
 	int i;
 
@@ -311,6 +313,33 @@ __elfN(get_brandinfo)(struct image_params *imgp, const char *interp,
 		}
 	}
 
+	/* Some ABI allows to run the interpreter itself. */
+	for (i = 0; i < MAX_BRANDS; i++) {
+		bi = elf_brand_list[i];
+		if (bi == NULL || bi->flags & BI_BRAND_NOTE_MANDATORY)
+			continue;
+		if (hdr->e_machine != bi->machine ||
+		    (bi->flags & BI_CAN_EXEC_INTERP) == 0)
+			continue;
+		/*
+		 * Compare the interpreter name not the path to allow run it
+		 * from everywhere.
+		 */
+		interp_brand_name = strrchr(bi->interp_path, '/');
+		if (interp_brand_name == NULL)
+			interp_brand_name = bi->interp_path;
+		interp_len = strlen(interp_brand_name);
+		fname_name = strrchr(imgp->args->fname, '/');
+		if (fname_name == NULL)
+			fname_name = imgp->args->fname;
+		fname_len = strlen(fname_name);
+		if (fname_len < interp_len)
+			continue;
+		ret = strncmp(fname_name, interp_brand_name, interp_len);
+		if (ret == 0)
+			return (bi);
+	}
+
 	/* Lacking a recognized interpreter, try the default brand */
 	for (i = 0; i < MAX_BRANDS; i++) {
 		bi = elf_brand_list[i];
diff --git a/sys/sys/imgact_elf.h b/sys/sys/imgact_elf.h
index faef5f8..3b34854 100644
--- a/sys/sys/imgact_elf.h
+++ b/sys/sys/imgact_elf.h
@@ -77,6 +77,7 @@ typedef struct {
 #define	BI_CAN_EXEC_DYN		0x0001
 #define	BI_BRAND_NOTE		0x0002	/* May have note.ABI-tag section. */
 #define	BI_BRAND_NOTE_MANDATORY	0x0004	/* Must have note.ABI-tag section. */
+#define	BI_CAN_EXEC_INTERP	0x0008	/* Allow to run interpreter itself. */
 } __ElfN(Brandinfo);
 
 __ElfType(Auxargs);