diff options
Diffstat (limited to 'src/is_tar.c')
| -rw-r--r-- | src/is_tar.c | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/src/is_tar.c b/src/is_tar.c index 876c631..1953a7f 100644 --- a/src/is_tar.c +++ b/src/is_tar.c @@ -40,7 +40,7 @@ #include "file.h" #ifndef lint -FILE_RCSID("@(#)$File: is_tar.c,v 1.37 2010/11/30 14:58:53 rrt Exp $") +FILE_RCSID("@(#)$File: is_tar.c,v 1.39 2017/03/17 20:45:01 christos Exp $") #endif #include "magic.h" @@ -51,7 +51,7 @@ FILE_RCSID("@(#)$File: is_tar.c,v 1.37 2010/11/30 14:58:53 rrt Exp $") #define isodigit(c) ( ((c) >= '0') && ((c) <= '7') ) private int is_tar(const unsigned char *, size_t); -private int from_oct(int, const char *); /* Decode octal number */ +private int from_oct(const char *, size_t); /* Decode octal number */ static const char tartype[][32] = { "tar archive", @@ -69,7 +69,7 @@ file_is_tar(struct magic_set *ms, const unsigned char *buf, size_t nbytes) int tar; int mime = ms->flags & MAGIC_MIME; - if ((ms->flags & MAGIC_APPLE) != 0) + if ((ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION)) != 0) return 0; tar = is_tar(buf, nbytes); @@ -93,31 +93,35 @@ private int is_tar(const unsigned char *buf, size_t nbytes) { const union record *header = (const union record *)(const void *)buf; - int i; - int sum, recsum; - const unsigned char *p; + size_t i; + int sum, recsum; + const unsigned char *p, *ep; - if (nbytes < sizeof(union record)) + if (nbytes < sizeof(*header)) return 0; - recsum = from_oct(8, header->header.chksum); + recsum = from_oct(header->header.chksum, sizeof(header->header.chksum)); sum = 0; p = header->charptr; - for (i = sizeof(union record); --i >= 0;) + ep = header->charptr + sizeof(*header); + while (p < ep) sum += *p++; /* Adjust checksum to count the "chksum" field as blanks. */ - for (i = sizeof(header->header.chksum); --i >= 0;) + for (i = 0; i < sizeof(header->header.chksum); i++) sum -= header->header.chksum[i]; - sum += ' ' * sizeof header->header.chksum; + sum += ' ' * sizeof(header->header.chksum); if (sum != recsum) return 0; /* Not a tar archive */ - if (strcmp(header->header.magic, GNUTMAGIC) == 0) + if (strncmp(header->header.magic, GNUTMAGIC, + sizeof(header->header.magic)) == 0) return 3; /* GNU Unix Standard tar archive */ - if (strcmp(header->header.magic, TMAGIC) == 0) + + if (strncmp(header->header.magic, TMAGIC, + sizeof(header->header.magic)) == 0) return 2; /* Unix Standard tar archive */ return 1; /* Old fashioned tar archive */ @@ -130,19 +134,22 @@ is_tar(const unsigned char *buf, size_t nbytes) * Result is -1 if the field is invalid (all blank, or non-octal). */ private int -from_oct(int digs, const char *where) +from_oct(const char *where, size_t digs) { int value; + if (digs == 0) + return -1; + while (isspace((unsigned char)*where)) { /* Skip spaces */ where++; - if (--digs <= 0) + if (digs-- == 0) return -1; /* All blank field */ } value = 0; while (digs > 0 && isodigit(*where)) { /* Scan til non-octal */ value = (value << 3) | (*where++ - '0'); - --digs; + digs--; } if (digs > 0 && *where && !isspace((unsigned char)*where)) |