From 8ab211a7ec728bb0ad8c766c8eeb12deb0a13b86 Mon Sep 17 00:00:00 2001 From: Guy Harris Date: Wed, 30 Sep 2020 11:37:30 -0700 Subject: [PATCH] Handle very large -f files by rejecting them. _read(), on Windows, has a 32-bit size argument and a 32-bit return value, so reject -f files that have more than 2^31-1 characters. Add some #defines so that, on Windows, we use _fstati64 to get the size of that file, to handle large files. Don't assume that our definition for ssize_t is the same size as size_t; by the time we want to print the return value of the read, we know it'll fit into an int, so just cast it to int and print it with %d. (cherry picked from commit faf8fb70af3a013e5d662b8283dec742fd6b1a77) --- netdissect-stdinc.h | 16 +++++++++++++++- tcpdump.c | 15 ++++++++++++--- 2 files changed, 27 insertions(+), 4 deletions(-) --- a/netdissect-stdinc.h +++ b/netdissect-stdinc.h @@ -149,10 +149,17 @@ #ifdef _MSC_VER #define stat _stat #define open _open -#define fstat _fstat #define read _read #define close _close #define O_RDONLY _O_RDONLY + +/* + * We define our_fstat64 as _fstati64, and define our_statb as + * struct _stati64, so we get 64-bit file sizes. + */ +#define our_fstat _fstati64 +#define our_statb struct _stati64 + #endif /* _MSC_VER */ /* @@ -211,6 +218,13 @@ typedef char* caddr_t; #include +/* + * We should have large file support enabled, if it's available, + * so just use fstat as our_fstat and struct stat as our_statb. + */ +#define our_fstat fstat +#define our_statb struct stat + #endif /* _WIN32 */ #ifndef HAVE___ATTRIBUTE__ --- a/tcpdump.c +++ b/tcpdump.c @@ -108,6 +108,7 @@ The Regents of the University of Califor #endif /* HAVE_CAP_NG_H */ #endif /* HAVE_LIBCAP_NG */ +#include "netdissect-stdinc.h" #include "netdissect.h" #include "interface.h" #include "addrtoname.h" @@ -861,15 +862,22 @@ read_infile(char *fname) { register int i, fd, cc; register char *cp; - struct stat buf; + our_statb buf; fd = open(fname, O_RDONLY|O_BINARY); if (fd < 0) error("can't open %s: %s", fname, pcap_strerror(errno)); - if (fstat(fd, &buf) < 0) + if (our_fstat(fd, &buf) < 0) error("can't stat %s: %s", fname, pcap_strerror(errno)); + /* + * Reject files whose size doesn't fit into an int; a filter + * *that* large will probably be too big. + */ + if (buf.st_size > INT_MAX) + error("%s is too large", fname); + cp = malloc((u_int)buf.st_size + 1); if (cp == NULL) error("malloc(%d) for %s: %s", (u_int)buf.st_size + 1, @@ -878,7 +886,8 @@ read_infile(char *fname) if (cc < 0) error("read %s: %s", fname, pcap_strerror(errno)); if (cc != buf.st_size) - error("short read %s (%d != %d)", fname, cc, (int)buf.st_size); + error("short read %s (%d != %d)", fname, (int) cc, + (int)buf.st_size); close(fd); /* replace "# comment" with spaces */