Commit message: Limit string printing to 100 chars, and add flags I forgot in the previous
commit.
CVE: CVE-2014-9621
CWE: CWE-399
Vulnerability description: The ELF parser in file 5.16 through 5.21 allows remote attackers to cause a denial of service via a long string.

Project: file
File: readelf.c

do_core_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
    int swap, uint32_t namesz, uint32_t descsz,
    size_t noff, size_t doff, int *flags, size_t size, int clazz)
{
#ifdef ELFCORE
	int os_style = -1;
	/*
	 * Sigh.  The 2.0.36 kernel in Debian 2.1, at
	 * least, doesn't correctly implement name
	 * sections, in core dumps, as specified by
	 * the "Program Linking" section of "UNIX(R) System
	 * V Release 4 Programmer's Guide: ANSI C and
	 * Programming Support Tools", because my copy
	 * clearly says "The first 'namesz' bytes in 'name'
	 * contain a *null-terminated* [emphasis mine]
	 * character representation of the entry's owner
	 * or originator", but the 2.0.36 kernel code
	 * doesn't include the terminating null in the
	 * name....
	 */
	if ((namesz == 4 && strncmp((char *)&nbuf[noff], "CORE", 4) == 0) ||
	    (namesz == 5 && strcmp((char *)&nbuf[noff], "CORE") == 0)) {
		os_style = OS_STYLE_SVR4;
	} 

	if ((namesz == 8 && strcmp((char *)&nbuf[noff], "FreeBSD") == 0)) {
		os_style = OS_STYLE_FREEBSD;
	}

	if ((namesz >= 11 && strncmp((char *)&nbuf[noff], "NetBSD-CORE", 11)
	    == 0)) {
		os_style = OS_STYLE_NETBSD;
	}

	if (os_style != -1 && (*flags & FLAGS_DID_CORE_STYLE) == 0) {
		if (file_printf(ms, ", %s-style", os_style_names[os_style])
		    == -1)
			return 1;
		*flags |= FLAGS_DID_CORE_STYLE;
	}

	switch (os_style) {
	case OS_STYLE_NETBSD:
		if (type == NT_NETBSD_CORE_PROCINFO) {
			char sbuf[512];
			uint32_t signo;
			/*
			 * Extract the program name.  It is at
			 * offset 0x7c, and is up to 32-bytes,
			 * including the terminating NUL.
			 */
			if (file_printf(ms, ", from '%.31s'",
			    file_printable(sbuf, sizeof(sbuf),
			    (const char *)&nbuf[doff + 0x7c])) == -1)
				return 1;
			
			/*
			 * Extract the signal number.  It is at
			 * offset 0x08.
			 */
			(void)memcpy(&signo, &nbuf[doff + 0x08],
			    sizeof(signo));
			if (file_printf(ms, " (signal %u)",
			    elf_getu32(swap, signo)) == -1)
				return 1;
			*flags |= FLAGS_DID_CORE;
			return 1;
		}
		break;

	default:
		if (type == NT_PRPSINFO && *flags & FLAGS_IS_CORE) {
			size_t i, j;
			unsigned char c;
			/*
			 * Extract the program name.  We assume
			 * it to be 16 characters (that's what it
			 * is in SunOS 5.x and Linux).
			 *
			 * Unfortunately, it's at a different offset
			 * in various OSes, so try multiple offsets.
			 * If the characters aren't all printable,
			 * reject it.
			 */
			for (i = 0; i < NOFFSETS; i++) {
				unsigned char *cname, *cp;
				size_t reloffset = prpsoffsets(i);
				size_t noffset = doff + reloffset;
				size_t k;
				for (j = 0; j < 16; j++, noffset++,
				    reloffset++) {
					/*
					 * Make sure we're not past
					 * the end of the buffer; if
					 * we are, just give up.
					 */
					if (noffset >= size)
						goto tryanother;

					/*
					 * Make sure we're not past
					 * the end of the contents;
					 * if we are, this obviously
					 * isn't the right offset.
					 */
					if (reloffset >= descsz)
						goto tryanother;

					c = nbuf[noffset];
					if (c == '\0') {
						/*
						 * A '\0' at the
						 * beginning is
						 * obviously wrong.
						 * Any other '\0'
						 * means we're done.
						 */
						if (j == 0)
							goto tryanother;
						else
							break;
					} else {
						/*
						 * A nonprintable
						 * character is also
						 * wrong.
						 */
						if (!isprint(c) || isquote(c))
							goto tryanother;
					}
				}
				/*
				 * Well, that worked.
				 */

				/*
				 * Try next offsets, in case this match is
				 * in the middle of a string.
				 */
				for (k = i + 1 ; k < NOFFSETS; k++) {
					size_t no;
					int adjust = 1;
					if (prpsoffsets(k) >= prpsoffsets(i))
						continue;
					for (no = doff + prpsoffsets(k);
					     no < doff + prpsoffsets(i); no++)
						adjust = adjust
						         && isprint(nbuf[no]);
					if (adjust)
						i = k;
				}

				cname = (unsigned char *)
				    &nbuf[doff + prpsoffsets(i)];
				for (cp = cname; *cp && isprint(*cp); cp++)
					continue;
				/*
				 * Linux apparently appends a space at the end
				 * of the command line: remove it.
				 */
				while (cp > cname && isspace(cp[-1]))
					cp--;
				if (file_printf(ms, ", from '%.*s'",
				    (int)(cp - cname), cname) == -1)
					return 1;
				*flags |= FLAGS_DID_CORE;
				return 1;

			tryanother:
				;
			}
		}
		break;
	}
#endif
	return 0;
}

Project: file
File: readelf.c

do_os_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
    int swap, uint32_t namesz, uint32_t descsz,
    size_t noff, size_t doff, int *flags)
{
	if (namesz == 5 && strcmp((char *)&nbuf[noff], "SuSE") == 0 &&
	    type == NT_GNU_VERSION && descsz == 2) {
	    *flags |= FLAGS_DID_OS_NOTE;
	    file_printf(ms, ", for SuSE %d.%d", nbuf[doff], nbuf[doff + 1]);
	    return 1;
	}

	if (namesz == 4 && strcmp((char *)&nbuf[noff], "GNU") == 0 &&
	    type == NT_GNU_VERSION && descsz == 16) {
		uint32_t desc[4];
		(void)memcpy(desc, &nbuf[doff], sizeof(desc));

		*flags |= FLAGS_DID_OS_NOTE;
		if (file_printf(ms, ", for GNU/") == -1)
			return 1;
		switch (elf_getu32(swap, desc[0])) {
		case GNU_OS_LINUX:
			if (file_printf(ms, "Linux") == -1)
				return 1;
			break;
		case GNU_OS_HURD:
			if (file_printf(ms, "Hurd") == -1)
				return 1;
			break;
		case GNU_OS_SOLARIS:
			if (file_printf(ms, "Solaris") == -1)
				return 1;
			break;
		case GNU_OS_KFREEBSD:
			if (file_printf(ms, "kFreeBSD") == -1)
				return 1;
			break;
		case GNU_OS_KNETBSD:
			if (file_printf(ms, "kNetBSD") == -1)
				return 1;
			break;
		default:
			if (file_printf(ms, "<unknown>") == -1)
				return 1; 
		}
		if (file_printf(ms, " %d.%d.%d", elf_getu32(swap, desc[1]),
		    elf_getu32(swap, desc[2]), elf_getu32(swap, desc[3])) == -1)
			return 1;
		return 1;
	}

	if (namesz == 7 && strcmp((char *)&nbuf[noff], "NetBSD") == 0) {
	    	if (type == NT_NETBSD_VERSION && descsz == 4) {
			*flags |= FLAGS_DID_OS_NOTE;
			do_note_netbsd_version(ms, swap, &nbuf[doff]);
			return 1;
		}
	}

	if (namesz == 8 && strcmp((char *)&nbuf[noff], "FreeBSD") == 0) {
	    	if (type == NT_FREEBSD_VERSION && descsz == 4) {
			*flags |= FLAGS_DID_OS_NOTE;
			do_note_freebsd_version(ms, swap, &nbuf[doff]);
			return 1;
		}
	}

	if (namesz == 8 && strcmp((char *)&nbuf[noff], "OpenBSD") == 0 &&
	    type == NT_OPENBSD_VERSION && descsz == 4) {
		*flags |= FLAGS_DID_OS_NOTE;
		if (file_printf(ms, ", for OpenBSD") == -1)
			return 1;
		/* Content of note is always 0 */
		return 1;
	}

	if (namesz == 10 && strcmp((char *)&nbuf[noff], "DragonFly") == 0 &&
	    type == NT_DRAGONFLY_VERSION && descsz == 4) {
		uint32_t desc;
		*flags |= FLAGS_DID_OS_NOTE;
		if (file_printf(ms, ", for DragonFly") == -1)
			return 1;
		(void)memcpy(&desc, &nbuf[doff], sizeof(desc));
		desc = elf_getu32(swap, desc);
		if (file_printf(ms, " %d.%d.%d", desc / 100000,
		    desc / 10000 % 10, desc % 10000) == -1)
			return 1;
		return 1;
	}
	return 0;
}

Project: file
File: readelf.c

do_pax_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
    int swap, uint32_t namesz, uint32_t descsz,
    size_t noff, size_t doff, int *flags)
{
	if (namesz == 4 && strcmp((char *)&nbuf[noff], "PaX") == 0 &&
	    type == NT_NETBSD_PAX && descsz == 4) {
		static const char *pax[] = {
		    "+mprotect",
		    "-mprotect",
		    "+segvguard",
		    "-segvguard",
		    "+ASLR",
		    "-ASLR",
		};
		uint32_t desc;
		size_t i;
		int did = 0;

		*flags |= FLAGS_DID_NETBSD_PAX;
		(void)memcpy(&desc, &nbuf[doff], sizeof(desc));
		desc = elf_getu32(swap, desc);

		if (desc && file_printf(ms, ", PaX: ") == -1)
			return 1;

		for (i = 0; i < __arraycount(pax); i++) {
			if (((1 << i) & desc) == 0)
				continue;
			if (file_printf(ms, "%s%s", did++ ? "," : "",
			    pax[i]) == -1)
				return 1;
		}
		return 1;
	}
	return 0;
}

Project: file
File: readelf.c

dophn_core(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
    int num, size_t size, off_t fsize, int *flags, uint16_t *notecount)
{
	Elf32_Phdr ph32;
	Elf64_Phdr ph64;
	size_t offset, len;
	unsigned char nbuf[BUFSIZ];
	ssize_t bufsize;

	if (size != xph_sizeof) {
		if (file_printf(ms, ", corrupted program header size") == -1)
			return -1;
		return 0;
	}

	/*
	 * Loop through all the program headers.
	 */
	for ( ; num; num--) {
		if (pread(fd, xph_addr, xph_sizeof, off) < (ssize_t)xph_sizeof) {
			file_badread(ms);
			return -1;
		}
		off += size;

		if (fsize != SIZE_UNKNOWN && xph_offset > fsize) {
			/* Perhaps warn here */
			continue;
		}

		if (xph_type != PT_NOTE)
			continue;

		/*
		 * This is a PT_NOTE section; loop through all the notes
		 * in the section.
		 */
		len = xph_filesz < sizeof(nbuf) ? xph_filesz : sizeof(nbuf);
		if ((bufsize = pread(fd, nbuf, len, xph_offset)) == -1) {
			file_badread(ms);
			return -1;
		}
		offset = 0;
		for (;;) {
			if (offset >= (size_t)bufsize)
				break;
			offset = donote(ms, nbuf, offset, (size_t)bufsize,
			    clazz, swap, 4, flags, notecount);
			if (offset == 0)
				break;

		}
	}
	return 0;
}

Project: file

doshn(struct magic_set *ms, int clazz, int swap, int fd, off_t off, int num,
    size_t size, off_t fsize, int mach, int strtab, int *flags,
    uint16_t *notecount)
{
	Elf32_Shdr sh32;
	Elf64_Shdr sh64;
	int stripped = 1;
	size_t nbadcap = 0;
	void *nbuf;
	off_t noff, coff, name_off;
	uint64_t cap_hw1 = 0;	/* SunOS 5.x hardware capabilites */
	uint64_t cap_sf1 = 0;	/* SunOS 5.x software capabilites */
	char name[50];
	ssize_t namesize;

	if (size != xsh_sizeof) {
		if (file_printf(ms, ", corrupted section header size") == -1)
			return -1;
		return 0;
	}

	/* Read offset of name section to be able to read section names later */
	if (pread(fd, xsh_addr, xsh_sizeof, off + size * strtab) < (ssize_t)xsh_sizeof) {
		file_badread(ms);
		return -1;
	}
	name_off = xsh_offset;

	for ( ; num; num--) {
		/* Read the name of this section. */
		if ((namesize = pread(fd, name, sizeof(name) - 1, name_off + xsh_name)) == -1) {
			file_badread(ms);
			return -1;
		}
		name[namesize] = '\0';
		if (strcmp(name, ".debug_info") == 0)
			stripped = 0;

		if (pread(fd, xsh_addr, xsh_sizeof, off) < (ssize_t)xsh_sizeof) {
			file_badread(ms);
			return -1;
		}
		off += size;

		/* Things we can determine before we seek */
		switch (xsh_type) {
		case SHT_SYMTAB:
#if 0
		case SHT_DYNSYM:
#endif
			stripped = 0;
			break;
		default:
			if (fsize != SIZE_UNKNOWN && xsh_offset > fsize) {
				/* Perhaps warn here */
				continue;
			}
			break;
		}

		/* Things we can determine when we seek */
		switch (xsh_type) {
		case SHT_NOTE:
			if ((nbuf = malloc(xsh_size)) == NULL) {
				file_error(ms, errno, "Cannot allocate memory"
				    " for note");
				return -1;
			}
			if (pread(fd, nbuf, xsh_size, xsh_offset) < (ssize_t)xsh_size) {
				file_badread(ms);
				free(nbuf);
				return -1;
			}

			noff = 0;
			for (;;) {
				if (noff >= (off_t)xsh_size)
					break;
				noff = donote(ms, nbuf, (size_t)noff,
				    xsh_size, clazz, swap, 4, flags, notecount);
				if (noff == 0)
					break;
			}
			free(nbuf);
			break;
		case SHT_SUNW_cap:
			switch (mach) {
			case EM_SPARC:
			case EM_SPARCV9:
			case EM_IA_64:
			case EM_386:
			case EM_AMD64:
				break;
			default:
				goto skip;
			}

			if (nbadcap > 5)
				break;
			if (lseek(fd, xsh_offset, SEEK_SET) == (off_t)-1) {
				file_badseek(ms);
				return -1;
			}
			coff = 0;
			for (;;) {
				Elf32_Cap cap32;
				Elf64_Cap cap64;
				char cbuf[/*CONSTCOND*/
				    MAX(sizeof cap32, sizeof cap64)];
				if ((coff += xcap_sizeof) > (off_t)xsh_size)
					break;
				if (read(fd, cbuf, (size_t)xcap_sizeof) !=
				    (ssize_t)xcap_sizeof) {
					file_badread(ms);
					return -1;
				}
				if (cbuf[0] == 'A') {
#ifdef notyet
					char *p = cbuf + 1;
					uint32_t len, tag;
					memcpy(&len, p, sizeof(len));
					p += 4;
					len = getu32(swap, len);
					if (memcmp("gnu", p, 3) != 0) {
					    if (file_printf(ms,
						", unknown capability %.3s", p)
						== -1)
						return -1;
					    break;
					}
					p += strlen(p) + 1;
					tag = *p++;
					memcpy(&len, p, sizeof(len));
					p += 4;
					len = getu32(swap, len);
					if (tag != 1) {
					    if (file_printf(ms, ", unknown gnu"
						" capability tag %d", tag)
						== -1)
						return -1;
					    break;
					}
#endif
					break;
				}
				(void)memcpy(xcap_addr, cbuf, xcap_sizeof);
				switch (xcap_tag) {
				case CA_SUNW_NULL:
					break;
				case CA_SUNW_HW_1:
					cap_hw1 |= xcap_val;
					break;
				case CA_SUNW_SF_1:
					cap_sf1 |= xcap_val;
					break;
				default:
					if (file_printf(ms,
					    ", with unknown capability "
					    "0x%" INT64_T_FORMAT "x = 0x%"
					    INT64_T_FORMAT "x",
					    (unsigned long long)xcap_tag,
					    (unsigned long long)xcap_val) == -1)
						return -1;
					if (nbadcap++ > 2)
						coff = xsh_size;
					break;
				}
			}
			/*FALLTHROUGH*/
		skip:
		default:
			break;
		}
	}

	if (file_printf(ms, ", %sstripped", stripped ? "" : "not ") == -1)
		return -1;
	if (cap_hw1) {
		const cap_desc_t *cdp;
		switch (mach) {
		case EM_SPARC:
		case EM_SPARC32PLUS:
		case EM_SPARCV9:
			cdp = cap_desc_sparc;
			break;
		case EM_386:
		case EM_IA_64:
		case EM_AMD64:
			cdp = cap_desc_386;
			break;
		default:
			cdp = NULL;
			break;
		}
		if (file_printf(ms, ", uses") == -1)
			return -1;
		if (cdp) {
			while (cdp->cd_name) {
				if (cap_hw1 & cdp->cd_mask) {
					if (file_printf(ms,
					    " %s", cdp->cd_name) == -1)
						return -1;
					cap_hw1 &= ~cdp->cd_mask;
				}
				++cdp;
			}
			if (cap_hw1)
				if (file_printf(ms,
				    " unknown hardware capability 0x%"
				    INT64_T_FORMAT "x",
				    (unsigned long long)cap_hw1) == -1)
					return -1;
		} else {
			if (file_printf(ms,
			    " hardware capability 0x%" INT64_T_FORMAT "x",
			    (unsigned long long)cap_hw1) == -1)
				return -1;
		}
	}
	if (cap_sf1) {
		if (cap_sf1 & SF1_SUNW_FPUSED) {
			if (file_printf(ms,
			    (cap_sf1 & SF1_SUNW_FPKNWN)
			    ? ", uses frame pointer"
			    : ", not known to use frame pointer") == -1)
				return -1;
		}
		cap_sf1 &= ~SF1_SUNW_MASK;
		if (cap_sf1)
			if (file_printf(ms,
			    ", with unknown software capability 0x%"
			    INT64_T_FORMAT "x",
			    (unsigned long long)cap_sf1) == -1)
				return -1;
	}
	return 0;
}

Project: file
File: readelf.c

file_tryelf(struct magic_set *ms, int fd, const unsigned char *buf,
    size_t nbytes)
{
	union {
		int32_t l;
		char c[sizeof (int32_t)];
	} u;
	int clazz;
	int swap;
	struct stat st;
	off_t fsize;
	int flags = 0;
	Elf32_Ehdr elf32hdr;
	Elf64_Ehdr elf64hdr;
	uint16_t type, phnum, shnum, notecount;

	if (ms->flags & (MAGIC_MIME|MAGIC_APPLE))
		return 0;
	/*
	 * ELF executables have multiple section headers in arbitrary
	 * file locations and thus file(1) cannot determine it from easily.
	 * Instead we traverse thru all section headers until a symbol table
	 * one is found or else the binary is stripped.
	 * Return immediately if it's not ELF (so we avoid pipe2file unless needed).
	 */
	if (buf[EI_MAG0] != ELFMAG0
	    || (buf[EI_MAG1] != ELFMAG1 && buf[EI_MAG1] != OLFMAG1)
	    || buf[EI_MAG2] != ELFMAG2 || buf[EI_MAG3] != ELFMAG3)
		return 0;

	/*
	 * If we cannot seek, it must be a pipe, socket or fifo.
	 */
	if((lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) && (errno == ESPIPE))
		fd = file_pipe2file(ms, fd, buf, nbytes);

	if (fstat(fd, &st) == -1) {
  		file_badread(ms);
		return -1;
	}
	if (S_ISREG(st.st_mode) || st.st_size != 0)
		fsize = st.st_size;
	else
		fsize = SIZE_UNKNOWN;

	clazz = buf[EI_CLASS];

	switch (clazz) {
	case ELFCLASS32:
#undef elf_getu
#define elf_getu(a, b)	elf_getu32(a, b)
#undef elfhdr
#define elfhdr elf32hdr
#include "elfclass.h"
	case ELFCLASS64:
#undef elf_getu
#define elf_getu(a, b)	elf_getu64(a, b)
#undef elfhdr
#define elfhdr elf64hdr
#include "elfclass.h"
	default:
	    if (file_printf(ms, ", unknown class %d", clazz) == -1)
		    return -1;
	    break;
	}
	return 0;
}

Project: file
File: readelf.c

toomany(struct magic_set *ms, const char *name, uint16_t num)
{
	if (file_printf(ms, ", too many %s (%u)", name, num
	    ) == -1)
		return -1;
	return 0;
}