diff --git a/config.h.in b/config.h.in index 0adc903..366e639 100644 --- a/config.h.in +++ b/config.h.in @@ -758,6 +758,9 @@ /* Define if you have the pselect function. */ #undef HAVE_PSELECT +/* Define if you have the pread function. */ +#undef HAVE_PREAD + /* Define if you have the putenv function. */ #undef HAVE_PUTENV @@ -956,6 +959,9 @@ /* Define if you have the header file. */ #undef HAVE_DLFCN_H +/* Define if you have the header file. */ +#undef HAVE_ELF_H + /* Define if you have the header file. */ #undef HAVE_GRP_H diff --git a/configure.ac b/configure.ac index 2c74f13..4e9c3a4 100644 --- a/configure.ac +++ b/configure.ac @@ -782,7 +782,7 @@ dnl checks for system calls AC_CHECK_FUNCS(dup2 eaccess fcntl getdtablesize getgroups gethostname \ getpagesize getpeername getrlimit getrusage gettimeofday \ kill killpg lstat pselect readlink select setdtablesize \ - setitimer tcgetpgrp uname ulimit waitpid) + setitimer tcgetpgrp uname ulimit waitpid pread) AC_REPLACE_FUNCS(rename) dnl checks for c library functions diff --git a/execute_cmd.c b/execute_cmd.c index 4eae19c..0af6f8f 100644 --- a/execute_cmd.c +++ b/execute_cmd.c @@ -41,6 +41,10 @@ # include #endif +#ifdef HAVE_ELF_H +# include +#endif + #include "posixtime.h" #if defined (HAVE_SYS_RESOURCE_H) && !defined (RLIMTYPE) @@ -5706,6 +5710,14 @@ shell_execve (command, args, env) { /* The file has the execute bits set, but the kernel refuses to run it for some reason. See why. */ +#if defined (HAVE_HASH_BANG_EXEC) || defined (HAVE_ELF_H) + int fd = open (command, O_RDONLY); + + if (fd >= 0) + sample_len = read (fd, sample, sizeof (sample)); + else + sample_len = -1; +#endif #if defined (HAVE_HASH_BANG_EXEC) READ_SAMPLE_BUF (command, sample, sample_len); if (sample_len > 0) @@ -5715,6 +5727,7 @@ shell_execve (command, args, env) char *interp; int ilen; + close (fd); interp = getinterp (sample, sample_len, (int *)NULL); ilen = strlen (interp); errno = i; @@ -5730,7 +5743,138 @@ shell_execve (command, args, env) return (EX_NOEXEC); } #endif - errno = i; +#if defined (HAVE_ELF_H) + if (i == ENOENT + && sample_len > EI_NIDENT + && memcmp (sample, ELFMAG, SELFMAG) == 0) + { + off_t offset = -1; + + /* It is an ELF file. Now determine whether it is dynamically + linked and if yes, get the offset of the interpreter + string. */ + if (sample[EI_CLASS] == ELFCLASS32 + && sample_len > sizeof (Elf32_Ehdr)) + { + Elf32_Ehdr ehdr; + Elf32_Phdr *phdr; + int nphdr; + + /* We have to copy the data since the sample buffer + might not be aligned correctly to be accessed as + an Elf32_Ehdr struct. */ + memcpy (&ehdr, sample, sizeof (Elf32_Ehdr)); + + nphdr = ehdr.e_phnum; + phdr = (Elf32_Phdr *) malloc (nphdr * ehdr.e_phentsize); + if (phdr != NULL) + { +#ifdef HAVE_PREAD + sample_len = pread (fd, phdr, nphdr * ehdr.e_phentsize, + ehdr.e_phoff); +#else + if (lseek (fd, ehdr.e_phoff, SEEK_SET) != -1) + sample_len = read (fd, phdr, + nphdr * ehdr.e_phentsize); + else + sample_len = -1; +#endif + if (sample_len == nphdr * ehdr.e_phentsize) + while (nphdr-- > 0) + if (phdr[nphdr].p_type == PT_INTERP) + { + offset = phdr[nphdr].p_offset; + break; + } + free (phdr); + } + } + else if (sample[EI_CLASS] == ELFCLASS64 + && sample_len > sizeof (Elf64_Ehdr)) + { + Elf64_Ehdr ehdr; + Elf64_Phdr *phdr; + int nphdr; + + /* We have to copy the data since the sample buffer + might not be aligned correctly to be accessed as + an Elf64_Ehdr struct. */ + memcpy (&ehdr, sample, sizeof (Elf64_Ehdr)); + + nphdr = ehdr.e_phnum; + phdr = (Elf64_Phdr *) malloc (nphdr * ehdr.e_phentsize); + if (phdr != NULL) + { +#ifdef HAVE_PREAD + sample_len = pread (fd, phdr, nphdr * ehdr.e_phentsize, + ehdr.e_phoff); +#else + if (lseek (fd, ehdr.e_phoff, SEEK_SET) != -1) + sample_len = read (fd, phdr, + nphdr * ehdr.e_phentsize); + else + sample_len = -1; +#endif + if (sample_len == nphdr * ehdr.e_phentsize) + while (nphdr-- > 0) + if (phdr[nphdr].p_type == PT_INTERP) + { + offset = phdr[nphdr].p_offset; + break; + } + free (phdr); + } + } + + if (offset != -1) + { + size_t maxlen = 0; + size_t actlen = 0; + char *interp = NULL; + + do + { + if (actlen == maxlen) + { + char *newinterp = realloc (interp, maxlen += 200); + if (newinterp == NULL) + { + actlen = 0; + break; + } + interp = newinterp; + +#ifdef HAVE_PREAD + actlen = pread (fd, interp, maxlen, offset); +#else + if (lseek (fd, offset, SEEK_SET) != -1) + actlen = read (fd, interp, maxlen); + else + actlen = -1; +#endif + } + } + while (actlen > 0 && memchr (interp, '\0', actlen) == NULL); + + if (actlen > 0) + { + close (fd); + errno = i; + sys_error ("%s: %s: bad ELF interpreter", command, + interp); + free (interp); + return (EX_NOEXEC); + } + + free (interp); + } + } +#endif +#if defined (HAVE_HASH_BANG_EXEC) || defined (HAVE_ELF_H) + close (fd); +#endif + + errno = i; file_error (command); } return (last_command_exit_value); -- 2.17.2