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ftpd: fix command fetching to not do it in 1-byte reads;

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fix command de-escaping. Tested to download files with embeeded \xff and LF.
libbb: tweaks for the above

function                                             old     new   delta
ftpd_main                                           2231    2321     +90
xmalloc_fgets_internal                               190     222     +32
xmalloc_fgets_str_len                                  -      27     +27
xmalloc_fgets_str                                      7      23     +16
xmalloc_fgetline_str                                  10      26     +16
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/0 up/down: 181/0)             Total: 181 bytes
This commit is contained in:
Denis Vlasenko 2009-03-18 17:32:44 +00:00
parent fce4a9454c
commit 9f57cf6604
4 changed files with 80 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/libbb.h
View File

@ -594,9 +594,9 @@ extern ssize_t open_read_close(const char *filename, void *buf, size_t maxsz) FA
// Reads byte-by-byte. Useful when it is important to not read ahead.
// Bytes are appended to pfx (which must be malloced, or NULL).
extern char *xmalloc_reads(int fd, char *pfx, size_t *maxsz_p) FAST_FUNC;
/* Reads block up to *maxsz_p (default: MAX_INT(ssize_t)) */
/* Reads block up to *maxsz_p (default: INT_MAX - 4095) */
extern void *xmalloc_read(int fd, size_t *maxsz_p) FAST_FUNC;
/* Returns NULL if file can't be opened */
/* Returns NULL if file can't be opened (default max size: INT_MAX - 4095) */
extern void *xmalloc_open_read_close(const char *filename, size_t *maxsz_p) FAST_FUNC;
/* Autodetects .gz etc */
extern int open_zipped(const char *fname) FAST_FUNC;
@ -619,6 +619,8 @@ extern char *bb_get_chunk_from_file(FILE *file, int *end) FAST_FUNC;
extern char *bb_get_chunk_with_continuation(FILE *file, int *end, int *lineno) FAST_FUNC;
/* Reads up to (and including) TERMINATING_STRING: */
extern char *xmalloc_fgets_str(FILE *file, const char *terminating_string) FAST_FUNC;
/* Same, with limited max size, and returns the length (excluding NUL): */
extern char *xmalloc_fgets_str_len(FILE *file, const char *terminating_string, size_t *maxsz_p) FAST_FUNC;
/* Chops off TERMINATING_STRING from the end: */
extern char *xmalloc_fgetline_str(FILE *file, const char *terminating_string) FAST_FUNC;
/* Reads up to (and including) "\n" or NUL byte: */

26
libbb/fgets_str.c
View File

@ -10,7 +10,7 @@
#include "libbb.h"
static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string, int chop_off)
static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string, int chop_off, size_t *maxsz_p)
{
char *linebuf = NULL;
const int term_length = strlen(terminating_string);
@ -18,6 +18,7 @@ static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string,
int linebufsz = 0;
int idx = 0;
int ch;
size_t maxsz = *maxsz_p;
while (1) {
ch = fgetc(file);
@ -30,6 +31,11 @@ static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string,
if (idx >= linebufsz) {
linebufsz += 200;
linebuf = xrealloc(linebuf, linebufsz);
if (idx >= maxsz) {
linebuf[idx] = ch;
idx++;
break;
}
}
linebuf[idx] = ch;
@ -48,6 +54,7 @@ static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string,
/* Grow/shrink *first*, then store NUL */
linebuf = xrealloc(linebuf, idx + 1);
linebuf[idx] = '\0';
*maxsz_p = idx;
return linebuf;
}
@ -57,10 +64,23 @@ static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string,
* Return NULL if EOF is reached immediately. */
char* FAST_FUNC xmalloc_fgets_str(FILE *file, const char *terminating_string)
{
return xmalloc_fgets_internal(file, terminating_string, 0);
size_t maxsz = INT_MAX - 4095;
return xmalloc_fgets_internal(file, terminating_string, 0, &maxsz);
}
char* FAST_FUNC xmalloc_fgets_str_len(FILE *file, const char *terminating_string, size_t *maxsz_p)
{
size_t maxsz;
if (!maxsz_p) {
maxsz = INT_MAX - 4095;
maxsz_p = &maxsz;
}
return xmalloc_fgets_internal(file, terminating_string, 0, maxsz_p);
}
char* FAST_FUNC xmalloc_fgetline_str(FILE *file, const char *terminating_string)
{
return xmalloc_fgets_internal(file, terminating_string, 1);
size_t maxsz = INT_MAX - 4095;
return xmalloc_fgets_internal(file, terminating_string, 1, &maxsz);
}

6
libbb/read.c
View File

@ -141,7 +141,7 @@ char* FAST_FUNC xmalloc_reads(int fd, char *buf, size_t *maxsz_p)
{
char *p;
size_t sz = buf ? strlen(buf) : 0;
size_t maxsz = maxsz_p ? *maxsz_p : MAXINT(size_t);
size_t maxsz = maxsz_p ? *maxsz_p : (INT_MAX - 4095);
goto jump_in;
while (sz < maxsz) {
@ -198,7 +198,7 @@ void* FAST_FUNC xmalloc_read(int fd, size_t *maxsz_p)
size_t to_read;
struct stat st;
to_read = maxsz_p ? *maxsz_p : MAXINT(ssize_t); /* max to read */
to_read = maxsz_p ? *maxsz_p : (INT_MAX - 4095); /* max to read */
/* Estimate file size */
st.st_size = 0; /* in case fstat fails, assume 0 */
@ -262,7 +262,7 @@ void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *maxsz_p)
len = lseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
if (len != (off_t)-1) {
xlseek(fd, 0, SEEK_SET);
size = maxsz_p ? *maxsz_p : INT_MAX;
size = maxsz_p ? *maxsz_p : (INT_MAX - 4095);
if (len < size)
size = len;
}

63
networking/ftpd.c
View File

@ -972,23 +972,60 @@ cmdio_get_cmd_and_arg(void)
free(G.ftp_cmd);
len = 8 * 1024; /* Paranoia. Peer may send 1 gigabyte long cmd... */
G.ftp_cmd = cmd = xmalloc_reads(STDIN_FILENO, NULL, &len);
G.ftp_cmd = cmd = xmalloc_fgets_str_len(stdin, "\r\n", &len);
if (!cmd)
exit(0);
/* TODO: de-escape telnet here: 0xff,0xff => 0xff */
/* RFC959 says that ABOR, STAT, QUIT may be sent even during
* data transfer, and may be preceded by telnet's "Interrupt Process"
* code (two-byte sequence 255,244) and then by telnet "Synch" code
* 255,242 (byte 242 is sent with TCP URG bit using send(MSG_OOB)
* and may generate SIGURG on our side. See RFC854).
* So far we don't support that (may install SIGURG handler if we'd want to),
* but we need to at least remove 255,xxx pairs. lftp sends those. */
/* De-escape telnet: 0xff,0xff => 0xff */
/* RFC959 says that ABOR, STAT, QUIT may be sent even during
* data transfer, and may be preceded by telnet's "Interrupt Process"
* code (two-byte sequence 255,244) and then by telnet "Synch" code
* 255,242 (byte 242 is sent with TCP URG bit using send(MSG_OOB)
* and may generate SIGURG on our side. See RFC854).
* So far we don't support that (may install SIGURG handler if we'd want to),
* but we need to at least remove 255,xxx pairs. lftp sends those. */
/* Then de-escape FTP: NUL => '\n' */
/* Testing for \xff:
* Create file named '\xff': echo Hello >`echo -ne "\xff"`
* Try to get it: ftpget -v 127.0.0.1 Eff `echo -ne "\xff\xff"`
* (need "\xff\xff" until ftpget applet is fixed to do escaping :)
* Testing for embedded LF:
* LF_HERE=`echo -ne "LF\nHERE"`
* echo Hello >"$LF_HERE"
* ftpget -v 127.0.0.1 LF_HERE "$LF_HERE"
*/
{
int dst, src;
/* Trailing '\n' is already stripped, strip '\r' */
len = strlen(cmd) - 1;
if ((ssize_t)len >= 0 && cmd[len] == '\r')
cmd[len--] = '\0';
/* Strip "\r\n" if it is there */
if (len != 0 && cmd[len - 1] == '\n') {
len--;
if (len != 0 && cmd[len - 1] == '\r')
len--;
cmd[len] = '\0';
}
src = strchrnul(cmd, 0xff) - cmd;
/* 99,99% there are neither NULs nor 255s and src == len */
if (src < len) {
dst = src;
do {
if ((unsigned char)(cmd[src]) == 255) {
src++;
/* 255,xxx - skip 255 */
if ((unsigned char)(cmd[src]) != 255) {
/* 255,!255 - skip both */
src++;
continue;
}
/* 255,255 - retain one 255 */
}
/* NUL => '\n' */
cmd[dst++] = cmd[src] ? cmd[src] : '\n';
src++;
} while (src < len);
cmd[dst] = '\0';
}
}
if (G.verbose > 1)
verbose_log(cmd);