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apps/nshlib/nsh_parse.c: Fixes an error in the NSH parser. There was a bug when executing an nsh shell script which contains a redirection. When the command in the script is executed, it sets the vtbl->np.np_redirect flag (as it should), but then doesn't restore it, leaving it set at the end of the script execution. Then the vtbl->np.np_redirect flag is set when the 'sh' command completes, causing a restore from un-initialized variables, thus leading to a crash. See the code snippet below for an example test case.

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Test case:

NuttShell (NSH)
nsh> mkrd -s 1024 40
nsh> mkfatfs /dev/ram0
nsh> mount -t vfat /dev/ram0 /tmp
nsh> echo "echo 1 > /dev/null" > /tmp/test.sh
nsh> cat /tmp/test.sh
echo 1 > /dev/null
nsh> sh /tmp/test.sh
...

The nsh prompt doesn't get printed.  You can type a couple of commands, but then the system will crash because of bad pointers.
This commit is contained in:
Ken Pettit
2019-01-12 10:56:48 -06:00
committed by Gregory Nutt
parent eaec674e7b
commit e08d100919
1 changed files with 6 additions and 0 deletions
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6
nshlib/nsh_parse.c
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@@ -2332,6 +2332,9 @@ static int nsh_parse_command(FAR struct nsh_vtbl_s *vtbl, FAR char *cmdline)
int oflags = 0; int oflags = 0;
int argc; int argc;
int ret; int ret;
#if CONFIG_NFILE_STREAMS > 0
bool redirect_save;
#endif
/* Initialize parser state */ /* Initialize parser state */
@@ -2500,6 +2503,7 @@ static int nsh_parse_command(FAR struct nsh_vtbl_s *vtbl, FAR char *cmdline)
if (strcmp(argv[argc-2], g_redirect1) == 0) if (strcmp(argv[argc-2], g_redirect1) == 0)
{ {
redirect_save = vtbl->np.np_redirect;
vtbl->np.np_redirect = true; vtbl->np.np_redirect = true;
oflags = O_WRONLY|O_CREAT|O_TRUNC; oflags = O_WRONLY|O_CREAT|O_TRUNC;
redirfile = nsh_getfullpath(vtbl, argv[argc-1]); redirfile = nsh_getfullpath(vtbl, argv[argc-1]);
@@ -2510,6 +2514,7 @@ static int nsh_parse_command(FAR struct nsh_vtbl_s *vtbl, FAR char *cmdline)
else if (strcmp(argv[argc-2], g_redirect2) == 0) else if (strcmp(argv[argc-2], g_redirect2) == 0)
{ {
redirect_save = vtbl->np.np_redirect;
vtbl->np.np_redirect = true; vtbl->np.np_redirect = true;
oflags = O_WRONLY|O_CREAT|O_APPEND; oflags = O_WRONLY|O_CREAT|O_APPEND;
redirfile = nsh_getfullpath(vtbl, argv[argc-1]); redirfile = nsh_getfullpath(vtbl, argv[argc-1]);
@@ -2537,6 +2542,7 @@ static int nsh_parse_command(FAR struct nsh_vtbl_s *vtbl, FAR char *cmdline)
if (redirfile) if (redirfile)
{ {
nsh_freefullpath(redirfile); nsh_freefullpath(redirfile);
vtbl->np.np_redirect = redirect_save;
} }
#endif #endif