handle any bitsize / endian type

1 files changed, 54 insertions, 26 deletions

diff --git a/paxelf.h b/paxelf.h
index f7a72ae..730b57e 100644
--- a/paxelf.h
+++ b/paxelf.h
@@ -9,6 +9,7 @@
 #ifdef __linux__
 # include <elf.h>
 # include <asm/elf.h>
+# include <byteswap.h>
 #else
 # include <sys/elf_common.h>
 #endif
@@ -17,30 +18,51 @@
 # error "UNABLE TO DETECT ELF_CLASS"
 #endif
 
-/* we need to hide bitsize (32/64) and endian (little/big) */
-
-#if (ELF_CLASS == ELFCLASS32)
-# define Elf_Ehdr Elf32_Ehdr
-# define Elf_Phdr Elf32_Phdr
-# define Elf_Shdr Elf32_Shdr
-# define Elf_Dyn  Elf32_Dyn
-#endif
-
-#if (ELF_CLASS == ELFCLASS64)
-# define Elf_Ehdr Elf64_Ehdr
-# define Elf_Phdr Elf64_Phdr
-# define Elf_Shdr Elf64_Shdr
-# define Elf_Dyn  Elf64_Dyn
-#endif
+extern char do_reverse_endian;
+/* Get a value 'X' in the elf header, compensating for endianness. */
+#define EGET(X) \
+	(__extension__ ({ \
+		uint64_t __res; \
+		if (!do_reverse_endian) {    __res = (X); \
+		} else if (sizeof(X) == 1) { __res = (X); \
+		} else if (sizeof(X) == 2) { __res = bswap_16((X)); \
+		} else if (sizeof(X) == 4) { __res = bswap_32((X)); \
+		} else if (sizeof(X) == 8) { __res = bswap_64((X)); \
+		} else { \
+			fprintf(stderr, "EGET failed ;(\n"); \
+			exit(EXIT_FAILURE); \
+		} \
+		__res; \
+	}))
+/* Set a value 'Y' in the elf header to 'X', compensating for endianness. */
+#define ESET(Y,X) \
+	do if (!do_reverse_endian) { Y = (X); \
+	} else if (sizeof(Y) == 1) { Y = (X); \
+	} else if (sizeof(Y) == 2) { Y = bswap_16((uint16_t)(X)); \
+	} else if (sizeof(Y) == 4) { Y = bswap_32((uint32_t)(X)); \
+	} else if (sizeof(Y) == 8) { Y = bswap_64((uint64_t)(X)); \
+	} else { \
+		fprintf(stderr, "ESET failed ;(\n")); \
+		exit(EXIT_FAILURE); \
+	} while (0)
 
 typedef struct {
-	Elf_Ehdr *ehdr;
-	Elf_Phdr *phdr;
-	Elf_Shdr *shdr;
+	void *ehdr;
+	void *phdr;
+	void *shdr;
 	char *data;
+	char elf_class;
 	int len;
 	int fd;
 } elfobj;
+#define EHDR32(ptr) ((Elf32_Ehdr *)(ptr))
+#define EHDR64(ptr) ((Elf64_Ehdr *)(ptr))
+#define PHDR32(ptr) ((Elf32_Phdr *)(ptr))
+#define PHDR64(ptr) ((Elf64_Phdr *)(ptr))
+#define SHDR32(ptr) ((Elf32_Shdr *)(ptr))
+#define SHDR64(ptr) ((Elf64_Shdr *)(ptr))
+#define DYN32(ptr) ((Elf32_Dyn *)(ptr))
+#define DYN64(ptr) ((Elf64_Dyn *)(ptr))
 
 /* prototypes */
 extern char *pax_short_hf_flags(unsigned long flags);
@@ -48,15 +70,11 @@ extern char *pax_short_pf_flags(unsigned long flags);
 extern char *gnu_short_stack_flags(unsigned long flags);
 extern elfobj *readelf(const char *filename);
 extern void unreadelf(elfobj *elf);
-extern const char *get_elfetype(int type);
+extern const char *get_elfeitype(elfobj *elf, int ei_type, int type);
+extern const char *get_elfetype(elfobj *elf);
 extern const char *get_elfptype(int type);
 extern const char *get_elfdtype(int type);
-extern const char *elf_getsecname(elfobj *elf, Elf_Shdr *shdr);
-extern Elf_Shdr *elf_findsecbyname(elfobj *elf, const char *name);
-
-#define IS_ELF_TYPE(elf, type) (elf->ehdr->e_type == type)
-#define IS_ELF_ET_EXEC(elf) IS_ELF_TYPE(elf, ET_EXEC)
-#define IS_ELF_ET_DYN(elf)  IS_ELF_TYPE(elf, ET_DYN)
+extern void *elf_findsecbyname(elfobj *elf, const char *name);
 
 /* PaX flags (to be read in elfhdr.e_flags) */
 #define HF_PAX_PAGEEXEC		1	/* 0: Paging based non-exec pages */
@@ -67,7 +85,17 @@ extern Elf_Shdr *elf_findsecbyname(elfobj *elf, const char *name);
 #define HF_PAX_SEGMEXEC		32	/* 0: Segmentation based non-exec pages */
 
 #define EI_PAX			14	/* Index in e_ident[] where to read flags */
-#define PAX_FLAGS(elf) ((elf->ehdr->e_ident[EI_PAX + 1] << 8) + (elf->ehdr->e_ident[EI_PAX]))
+#define __PAX_FLAGS(B, elf) \
+	((EHDR ## B (elf->ehdr)->e_ident[EI_PAX + 1] << 8) + EHDR ## B (elf->ehdr)->e_ident[EI_PAX])
+#define PAX_FLAGS(elf) \
+	(__extension__ ({ \
+		unsigned long __res; \
+		if (elf->elf_class == ELFCLASS32) \
+			__res = __PAX_FLAGS(32, elf); \
+		else \
+			__res = __PAX_FLAGS(64, elf); \
+		__res; \
+	}))
 
 /*
  * in case we are not defined by proper/up-to-date system headers,