| Message ID | 1410997719-17913-1-git-send-email-todd.vierling@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Thanks for chasing this down, Todd! On Sep 17, 2014, at 4:48 PM, Todd Vierling <todd.vierling@oracle.com> wrote: > The original implementation was using strncpy() with a truncation > length to an uninitialized stack buffer, leaving a string that > was only null terminated by luck. > > While here, change to use no-copy semantics (no extra buffer) to > avoid buffer overflows altogether. Needs Fixes: 4663c648 (exportfs: Support raw IPv6 addresses with "client:/path”) And needs a Signed-off-by. I wonder about the “no-copy” change. I thought that on some systems, the tool chain makes the command line arguments read-only. > --- > utils/exportfs/exportfs.c | 18 ++++++++---------- > 1 file changed, 8 insertions(+), 10 deletions(-) > > diff --git a/utils/exportfs/exportfs.c b/utils/exportfs/exportfs.c > index e7d1ac8..bdea12b 100644 > --- a/utils/exportfs/exportfs.c > +++ b/utils/exportfs/exportfs.c > @@ -351,16 +351,15 @@ static int exportfs_generic(char *arg, char *options, int verbose) > > static int exportfs_ipv6(char *arg, char *options, int verbose) > { > - char *path, *c, hname[NI_MAXHOST + strlen("/128")]; > + char *path, *c; > > arg++; > c = strchr(arg, ']'); > if (c == NULL) > return 1; > - strncpy(hname, arg, c - arg); > > /* no colon means this is a wildcarded DNS hostname */ > - if (strchr(hname, ':') == NULL) > + if (memchr(arg, ':', c - arg) == NULL) > return exportfs_generic(--arg, options, verbose); > > path = strstr(c, ":/"); > @@ -370,9 +369,9 @@ static int exportfs_ipv6(char *arg, char *options, int verbose) > > /* if there's anything between the closing brace and the > * path separator, it's probably a prefix length */ > - strcat(hname, ++c); > + memmove(c, c + 1, path - c); > > - exportfs_parsed(hname, path, options, verbose); > + exportfs_parsed(arg, path, options, verbose); > return 0; > } > > @@ -458,16 +457,15 @@ static int unexportfs_generic(char *arg, int verbose) > > static int unexportfs_ipv6(char *arg, int verbose) > { > - char *path, *c, hname[NI_MAXHOST + strlen("/128")]; > + char *path, *c; > > arg++; > c = strchr(arg, ']'); > if (c == NULL) > return 1; > - strncpy(hname, arg, c - arg); > > /* no colon means this is a wildcarded DNS hostname */ > - if (strchr(hname, ':') == NULL) > + if (memchr(arg, ':', c - arg) == NULL) > return unexportfs_generic(--arg, verbose); > > path = strstr(c, ":/"); > @@ -477,9 +475,9 @@ static int unexportfs_ipv6(char *arg, int verbose) > > /* if there's anything between the closing brace and the > * path separator, it's probably a prefix length */ > - strcat(hname, ++c); > + memmove(c, c + 1, path - c); > > - unexportfs_parsed(hname, path, verbose); > + unexportfs_parsed(arg, path, verbose); > return 0; > } > > -- > 1.8.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Chuck Lever chucklever@gmail.com -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/utils/exportfs/exportfs.c b/utils/exportfs/exportfs.c index e7d1ac8..bdea12b 100644 --- a/utils/exportfs/exportfs.c +++ b/utils/exportfs/exportfs.c @@ -351,16 +351,15 @@ static int exportfs_generic(char *arg, char *options, int verbose) static int exportfs_ipv6(char *arg, char *options, int verbose) { - char *path, *c, hname[NI_MAXHOST + strlen("/128")]; + char *path, *c; arg++; c = strchr(arg, ']'); if (c == NULL) return 1; - strncpy(hname, arg, c - arg); /* no colon means this is a wildcarded DNS hostname */ - if (strchr(hname, ':') == NULL) + if (memchr(arg, ':', c - arg) == NULL) return exportfs_generic(--arg, options, verbose); path = strstr(c, ":/"); @@ -370,9 +369,9 @@ static int exportfs_ipv6(char *arg, char *options, int verbose) /* if there's anything between the closing brace and the * path separator, it's probably a prefix length */ - strcat(hname, ++c); + memmove(c, c + 1, path - c); - exportfs_parsed(hname, path, options, verbose); + exportfs_parsed(arg, path, options, verbose); return 0; } @@ -458,16 +457,15 @@ static int unexportfs_generic(char *arg, int verbose) static int unexportfs_ipv6(char *arg, int verbose) { - char *path, *c, hname[NI_MAXHOST + strlen("/128")]; + char *path, *c; arg++; c = strchr(arg, ']'); if (c == NULL) return 1; - strncpy(hname, arg, c - arg); /* no colon means this is a wildcarded DNS hostname */ - if (strchr(hname, ':') == NULL) + if (memchr(arg, ':', c - arg) == NULL) return unexportfs_generic(--arg, verbose); path = strstr(c, ":/"); @@ -477,9 +475,9 @@ static int unexportfs_ipv6(char *arg, int verbose) /* if there's anything between the closing brace and the * path separator, it's probably a prefix length */ - strcat(hname, ++c); + memmove(c, c + 1, path - c); - unexportfs_parsed(hname, path, verbose); + unexportfs_parsed(arg, path, verbose); return 0; }