appimage: calculate elf offset from file descriptor

3 files changed, 10 insertions, 16 deletions

diff --git a/src/firejail/appimage.c b/src/firejail/appimage.c
index cc66608d3..59758bf2d 100644
--- a/src/firejail/appimage.c
+++ b/src/firejail/appimage.c
@@ -61,7 +61,7 @@ void appimage_set(const char *appimage) {
 
         // get appimage type and ELF size
         // a value of 0 means we are dealing with a type1 appimage
-        size = appimage2_size(appimage);
+        size = appimage2_size(ffd);
         if (arg_debug)
                 printf("AppImage ELF size %lu\n", size);
 
diff --git a/src/firejail/appimage_size.c b/src/firejail/appimage_size.c
index 4640cb8a5..43ca501da 100644
--- a/src/firejail/appimage_size.c
+++ b/src/firejail/appimage_size.c
@@ -132,22 +132,20 @@ static long unsigned int read_elf64(int fd) {
 
 // return 0 if error
 // return 0 if this is not an appimgage2 file
-long unsigned int appimage2_size(const char *fname) {
+long unsigned int appimage2_size(int fd) {
         ssize_t ret;
-        int fd;
         long unsigned int size = 0;
 
-        fd = open(fname, O_RDONLY);
         if (fd < 0)
                 return 0;
 
         ret = pread(fd, ehdr.e_ident, EI_NIDENT, 0);
         if (ret != EI_NIDENT)
-                goto getout;
+                return 0;
 
         if ((ehdr.e_ident[EI_DATA] != ELFDATA2LSB) &&
              (ehdr.e_ident[EI_DATA] != ELFDATA2MSB))
-                goto getout;
+                return 0;
 
         if(ehdr.e_ident[EI_CLASS] == ELFCLASS32) {
                 size = read_elf32(fd);
@@ -156,23 +154,19 @@ long unsigned int appimage2_size(const char *fname) {
                 size = read_elf64(fd);
         }
         else {
-                goto getout;
+                return 0;
         }
         if (size == 0)
-                goto getout;
+                return 0;
 
 
         // look for a LZMA header at this location
         unsigned char buf[4];
         ret = pread(fd, buf, 4, size);
-        if (ret != 4) {
-                size = 0;
-                goto getout;
-        }
+        if (ret != 4)
+                return 0;
         if (memcmp(buf, "hsqs", 4) != 0)
-                size = 0;
+                return 0;
 
-getout:
-        close(fd);
         return size;
 }
diff --git a/src/firejail/firejail.h b/src/firejail/firejail.h
index 3b9a00c3f..ca4c988fa 100644
--- a/src/firejail/firejail.h
+++ b/src/firejail/firejail.h
@@ -802,7 +802,7 @@ void appimage_mount(void);
 void appimage_clear(void);
 
 // appimage_size.c
-long unsigned int appimage2_size(const char *fname);
+long unsigned int appimage2_size(int fd);
 
 // cmdline.c
 void build_cmdline(char **command_line, char **window_title, int argc, char **argv, int index);