Initialize varibles if reading fails

This way we don't do uninitizlied memory uses later on

oss-fuzz/21638

1 files changed, 30 insertions, 14 deletions

diff --git a/libspectre/ps.c b/libspectre/ps.c
index 0883670..bb45c9a 100644
--- a/libspectre/ps.c
+++ b/libspectre/ps.c
@@ -2209,6 +2209,28 @@ reorder_word(PS_WORD val)
 	return (PS_WORD) ((PS_WORD)(val&0xff) << 8) | (PS_WORD)((val&0xff00) >> 8);
 }
 
+static void
+ps_read_doseps_dword(FileData fd, PS_DWORD *dword)
+{
+    const size_t read = fread(dword, 4, 1, FD_FILE);
+    if (read == 4) {
+        *dword = (unsigned long)reorder_dword(*dword);
+    } else {
+        *dword = 0;
+    }
+}
+
+static void
+ps_read_doseps_word(FileData fd, PS_WORD *word)
+{
+    const size_t read = fread(word, 2, 1, FD_FILE);
+    if (read == 2) {
+        *word = (unsigned short)reorder_word(*word);
+    } else {
+        *word = 0;
+    }
+}
+
 /* DOS EPS header reading */
 static unsigned long
 ps_read_doseps(fd,doseps)
@@ -2222,20 +2244,14 @@ ps_read_doseps(fd,doseps)
         ps_io_rewind(fd);
 	return 0; 	/* OK */
     }
-    fread(&doseps->ps_begin,    4, 1, FD_FILE);	/* PS offset */
-    doseps->ps_begin = (unsigned long)reorder_dword(doseps->ps_begin);
-    fread(&doseps->ps_length,   4, 1, FD_FILE);	/* PS length */
-    doseps->ps_length = (unsigned long)reorder_dword(doseps->ps_length);
-    fread(&doseps->mf_begin,    4, 1, FD_FILE);	/* Metafile offset */
-    doseps->mf_begin = (unsigned long)reorder_dword(doseps->mf_begin);
-    fread(&doseps->mf_length,   4, 1, FD_FILE);	/* Metafile length */
-    doseps->mf_length = (unsigned long)reorder_dword(doseps->mf_length);
-    fread(&doseps->tiff_begin,  4, 1, FD_FILE);	/* TIFF offset */
-    doseps->tiff_begin = (unsigned long)reorder_dword(doseps->tiff_begin);
-    fread(&doseps->tiff_length, 4, 1, FD_FILE);	/* TIFF length */
-    doseps->tiff_length = (unsigned long)reorder_dword(doseps->tiff_length);
-    fread(&doseps->checksum,    2, 1, FD_FILE);
-    doseps->checksum = (unsigned short)reorder_word(doseps->checksum);
+    ps_read_doseps_dword(fd, &doseps->ps_begin); /* PS offset */
+    ps_read_doseps_dword(fd, &doseps->ps_length); /* PS length */
+    ps_read_doseps_dword(fd, &doseps->mf_begin); /* Metafile offset */
+    ps_read_doseps_dword(fd, &doseps->mf_length); /* Metafile length */
+    ps_read_doseps_dword(fd, &doseps->tiff_begin); /* TIFF offset */
+    ps_read_doseps_dword(fd, &doseps->tiff_length); /* TIFF length */
+    ps_read_doseps_word(fd, &doseps->checksum);
+
     ps_io_fseek(fd, doseps->ps_begin);	        /* seek to PS section */
 
     return doseps->ps_begin + doseps->ps_length;