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Sftp command underflow #911

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e74fd71
Fix underflow in sftp example with empty args
padelsbach Apr 9, 2026
d854f03
Move sftp test cases into a table for stronger linkage to expected be…
padelsbach Apr 9, 2026
94b8271
Cleanup sftp test artifacts at start of test
padelsbach Apr 9, 2026
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16 changes: 8 additions & 8 deletions examples/sftpclient/sftpclient.c
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Original file line number Diff line number Diff line change
Expand Up @@ -472,7 +472,7 @@ static int doCmds(func_args* args)
pt += sizeof("mkdir");
sz = (int)WSTRLEN(pt);

if (pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (sz > 0 && pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (pt[0] != '/') {
int maxSz = (int)WSTRLEN(workingDir) + sz + 2;
f = (char*)WMALLOC(maxSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);
Expand Down Expand Up @@ -522,7 +522,7 @@ static int doCmds(func_args* args)
pt += sizeof("get");

sz = (int)WSTRLEN(pt);
if (pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (sz > 0 && pt[sz - 1] == '\n') pt[sz - 1] = '\0';

/* search for space delimiter */
to = pt;
Expand Down Expand Up @@ -633,7 +633,7 @@ static int doCmds(func_args* args)
pt += sizeof("put");
sz = (int)WSTRLEN(pt);

if (pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (sz > 0 && pt[sz - 1] == '\n') pt[sz - 1] = '\0';

to = pt;
for (i = 0; i < sz; i++) {
Expand Down Expand Up @@ -739,7 +739,7 @@ static int doCmds(func_args* args)
pt += sizeof("cd");
sz = (int)WSTRLEN(pt);

if (pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (sz > 0 && pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (pt[0] != '/') {
int maxSz = (int)WSTRLEN(workingDir) + sz + 2;
f = (char*)WMALLOC(maxSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);
Expand Down Expand Up @@ -803,7 +803,7 @@ static int doCmds(func_args* args)
pt += sizeof("chmod");
sz = (word32)WSTRLEN(pt);

if (pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (sz > 0 && pt[sz - 1] == '\n') pt[sz - 1] = '\0';

/* advance pointer to first location of non space character */
for (idx = 0; idx < sz && pt[0] == ' '; idx++, pt++);
Expand Down Expand Up @@ -885,7 +885,7 @@ static int doCmds(func_args* args)
pt += sizeof("rmdir");
sz = (int)WSTRLEN(pt);

if (pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (sz > 0 && pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (pt[0] != '/') {
int maxSz = (int)WSTRLEN(workingDir) + sz + 2;
f = (char*)WMALLOC(maxSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);
Expand Down Expand Up @@ -942,7 +942,7 @@ static int doCmds(func_args* args)
pt += sizeof("rm");
sz = (int)WSTRLEN(pt);

if (pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (sz > 0 && pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (pt[0] != '/') {
int maxSz = (int)WSTRLEN(workingDir) + sz + 2;
f = (char*)WMALLOC(maxSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);
Expand Down Expand Up @@ -997,7 +997,7 @@ static int doCmds(func_args* args)
pt += sizeof("rename");
sz = (int)WSTRLEN(pt);

if (pt[sz - 1] == '\n') pt[sz - 1] = '\0';
if (sz > 0 && pt[sz - 1] == '\n') pt[sz - 1] = '\0';

/* search for space delimiter */
to = pt;
Expand Down
235 changes: 144 additions & 91 deletions tests/sftp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -43,108 +43,153 @@
#include "examples/echoserver/echoserver.h"
#include "examples/sftpclient/sftpclient.h"

static const char* cmds[] = {
"mkdir a",
"cd a",
"pwd",
"ls",
#ifdef WOLFSSH_ZEPHYR
"put " CONFIG_WOLFSSH_SFTP_DEFAULT_DIR "/configure.ac",
#else
"put configure.ac",
#endif
"ls",
#ifdef WOLFSSH_ZEPHYR
"get configure.ac " CONFIG_WOLFSSH_SFTP_DEFAULT_DIR "/test-get",
#else
"get configure.ac test-get",
#endif
"rm configure.ac",
"cd ../",
"ls",
"rename test-get test-get-2",
"rmdir a",
"ls",
"chmod 600 test-get-2",
"rm test-get-2",
"ls -s",
"exit"
};
static int commandIdx = 0;
/*
* Each test command is paired with an optional check function that
* validates the output it produces. This eliminates the fragile
* index-based coupling between the command array and the validator.
*/
typedef int (*SftpTestCheck)(void);

typedef struct {
const char* cmd;
SftpTestCheck check; /* validates output from THIS cmd, or NULL */
} SftpTestCmd;

/* Test buffer */
static char inBuf[1024] = {0};

/* return 0 on success */
static int Expected(int command)
/* check that pwd output ends in /a */
static int checkPwdInA(void)
{
int i;
int len;

switch (command) {
case 3: /* pwd */
/* working directory should not contain a '.' at the end */
for (i = 0; i < (int)sizeof(inBuf); i++) {
if (inBuf[i] == '\n') {
inBuf[i] = '\0';
break;
}
}

if (inBuf[WSTRLEN(inBuf) - 2] != '/') {
printf("unexpected pwd of %s\n looking for '/'\n", inBuf);
return -1;
}
if (inBuf[WSTRLEN(inBuf) - 1] != 'a') {
printf("unexpected pwd of %s\n looking for 'a'\n", inBuf);
return -1;
}
for (i = 0; i < (int)sizeof(inBuf); i++) {
if (inBuf[i] == '\n') {
inBuf[i] = '\0';
break;
}
}

case 4:
{
len = (int)WSTRLEN(inBuf);
if (len < 2) {
printf("pwd output too short: %s\n", inBuf);
return -1;
}
if (inBuf[len - 2] != '/') {
printf("unexpected pwd of %s, looking for '/'\n", inBuf);
return -1;
}
if (inBuf[len - 1] != 'a') {
printf("unexpected pwd of %s, looking for 'a'\n", inBuf);
return -1;
}
return 0;
}

/* check that ls of empty dir shows only . and .. */
static int checkLsEmpty(void)
{
#ifdef WOLFSSH_ZEPHYR
/* No . and .. in zephyr fs API */
char expt1[] = "wolfSSH sftp> ";
char expt2[] = "wolfSSH sftp> ";
/* No . and .. in zephyr fs API */
char expt1[] = "wolfSSH sftp> ";
char expt2[] = "wolfSSH sftp> ";
#else
char expt1[] = ".\n..\nwolfSSH sftp> ";
char expt2[] = "..\n.\nwolfSSH sftp> ";
char expt1[] = ".\n..\nwolfSSH sftp> ";
char expt2[] = "..\n.\nwolfSSH sftp> ";
#endif
if (WMEMCMP(expt1, inBuf, sizeof(expt1)) != 0 &&
WMEMCMP(expt2, inBuf, sizeof(expt2)) != 0) {
printf("unexpected ls\n");
printf("\texpected \n%s\n\tor\n%s\n\tbut got\n%s\n", expt1,
expt2, inBuf);
return -1;
}
else
return 0;

}

case 6:
if (WSTRNSTR(inBuf, "configure.ac", sizeof(inBuf)) == NULL) {
fprintf(stderr, "configure.ac not found in %s\n", inBuf);
return 1;
}
else {
return 0;
}
if (WMEMCMP(expt1, inBuf, sizeof(expt1)) != 0 &&
WMEMCMP(expt2, inBuf, sizeof(expt2)) != 0) {
printf("unexpected ls\n");
printf("\texpected \n%s\n\tor\n%s\n\tbut got\n%s\n",
expt1, expt2, inBuf);
return -1;
}
return 0;
}

case 10:
return (WSTRNSTR(inBuf, "test-get", sizeof(inBuf)) == NULL);
/* check that ls output contains a specific file */
static int checkLsHasConfigureAc(void)
{
if (WSTRNSTR(inBuf, "configure.ac", sizeof(inBuf)) == NULL) {
fprintf(stderr, "configure.ac not found in %s\n", inBuf);
return 1;
}
return 0;
}

case 13:
return (WSTRNSTR(inBuf, "test-get-2", sizeof(inBuf)) == NULL);
static int checkLsHasTestGet(void)
{
return (WSTRNSTR(inBuf, "test-get",
sizeof(inBuf)) == NULL) ? 1 : 0;
}

case 16:
return (WSTRNSTR(inBuf, "size in bytes", sizeof(inBuf)) == NULL);
static int checkLsHasTestGet2(void)
{
return (WSTRNSTR(inBuf, "test-get-2",
sizeof(inBuf)) == NULL) ? 1 : 0;
}

default:
break;
}
WMEMSET(inBuf, 0, sizeof(inBuf));
return 0;
static int checkLsSize(void)
{
return (WSTRNSTR(inBuf, "size in bytes",
sizeof(inBuf)) == NULL) ? 1 : 0;
}

static const SftpTestCmd cmds[] = {
/* If a prior run was interrupted, files and directories
* created during the test may still exist in the working
* directory, causing mkdir to fail and ls checks to see
* unexpected entries. Remove them here before starting.
* These run as SFTP commands rather than local syscalls
* so they are portable across all platforms (Windows,
* Zephyr, POSIX). Failures are silently ignored since
* the files may not exist. */
{ "rm a/configure.ac", NULL },
{ "rmdir a", NULL },
{ "rm test-get", NULL },
{ "rm test-get-2", NULL },

/* --- test sequence starts here --- */
{ "mkdir a", NULL },
{ "cd a", NULL },
{ "pwd", checkPwdInA },
{ "ls", checkLsEmpty },
#ifdef WOLFSSH_ZEPHYR
{ "put " CONFIG_WOLFSSH_SFTP_DEFAULT_DIR "/configure.ac", NULL },
#else
{ "put configure.ac", NULL },
#endif
{ "ls", checkLsHasConfigureAc },
#ifdef WOLFSSH_ZEPHYR
{ "get configure.ac "
CONFIG_WOLFSSH_SFTP_DEFAULT_DIR "/test-get", NULL },
#else
{ "get configure.ac test-get", NULL },
#endif
{ "rm configure.ac", NULL },
{ "cd ../", NULL },
{ "ls", checkLsHasTestGet },
{ "rename test-get test-get-2", NULL },
{ "rmdir a", NULL },
{ "ls", checkLsHasTestGet2 },
{ "chmod 600 test-get-2", NULL },
{ "rm test-get-2", NULL },
{ "ls -s", checkLsSize },
/* empty arg tests: must not underflow on pt[sz-1] */
{ "mkdir", NULL },
{ "cd", NULL },
{ "ls", NULL },
{ "chmod", NULL },
{ "rmdir", NULL },
{ "rm", NULL },
{ "rename", NULL },
{ "get", NULL },
{ "put", NULL },
{ "exit", NULL },
};
static int commandIdx = 0;


static int commandCb(const char* in, char* out, int outSz)
{
Expand All @@ -157,18 +202,26 @@ static int commandCb(const char* in, char* out, int outSz)

/* get command input */
if (out) {
int sz = (int)WSTRLEN(cmds[commandIdx]);
int sz = (int)WSTRLEN(cmds[commandIdx].cmd);
if (outSz < sz) {
ret = -1;
}
else {
WMEMCPY(out, cmds[commandIdx], sz);
WMEMCPY(out, cmds[commandIdx].cmd, sz);
}

if (Expected(commandIdx) != 0) {
fprintf(stderr, "Failed on command index %d\n", commandIdx);
exit(1); /* abort out */
/* validate output from the previous command */
if (commandIdx > 0 &&
cmds[commandIdx - 1].check != NULL) {
if (cmds[commandIdx - 1].check() != 0) {
fprintf(stderr,
"Check failed for \"%s\" (index %d)\n",
cmds[commandIdx - 1].cmd,
commandIdx - 1);
exit(1);
}
}
WMEMSET(inBuf, 0, sizeof(inBuf));
commandIdx++;
}
return ret;
Expand Down
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