Messages in this thread | | | Date | Mon, 4 Jan 2016 18:19:07 +0100 | From | Jan Kara <> | Subject | Re: [PATCH v2 2/7] udf: Check output buffer length when converting name to CS0 |
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On Thu 24-12-15 10:25:33, Andrew Gabbasov wrote: > If a name contains at least some characters with Unicode values > exceeding single byte, the CS0 output should have 2 bytes per character. > And if other input characters have single byte Unicode values, then > the single input byte is converted to 2 output bytes, and the length > of output becomes larger than the length of input. And if the input > name is long enough, the output length may exceed the allocated buffer > length. > > All this means that conversion from UTF8 or NLS to CS0 requires > checking of output length in order to stop when it exceeds the given > output buffer size. > > Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
I have taken this patch to my tree with a slight modification that udf_xxxtoCS0 functions return 0 when they would need to truncate the name. That way we properly return ENAMETOOLONG when user tries to create name we cannot store instead of silently truncating it.
Honza > --- > fs/udf/unicode.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c > index 95a224b..155f912 100644 > --- a/fs/udf/unicode.c > +++ b/fs/udf/unicode.c > @@ -177,17 +177,18 @@ int udf_CS0toUTF8(struct ustr *utf_o, const struct ustr *ocu_i) > static int udf_UTF8toCS0(dstring *ocu, struct ustr *utf, int length) > { > unsigned c, i, max_val, utf_char; > - int utf_cnt, u_len; > + int utf_cnt, u_len, u_ch; > > memset(ocu, 0, sizeof(dstring) * length); > ocu[0] = 8; > max_val = 0xffU; > + u_ch = 1; > > try_again: > u_len = 0U; > utf_char = 0U; > utf_cnt = 0U; > - for (i = 0U; i < utf->u_len; i++) { > + for (i = 0U; (i < utf->u_len) && ((u_len + 1 + u_ch) < length); i++) { > c = (uint8_t)utf->u_name[i]; > > /* Complete a multi-byte UTF-8 character */ > @@ -229,6 +230,7 @@ try_again: > if (max_val == 0xffU) { > max_val = 0xffffU; > ocu[0] = (uint8_t)0x10U; > + u_ch = 2; > goto try_again; > } > goto error_out; > @@ -299,15 +301,16 @@ static int udf_NLStoCS0(struct nls_table *nls, dstring *ocu, struct ustr *uni, > int len; > unsigned i, max_val; > uint16_t uni_char; > - int u_len; > + int u_len, u_ch; > > memset(ocu, 0, sizeof(dstring) * length); > ocu[0] = 8; > max_val = 0xffU; > + u_ch = 1; > > try_again: > u_len = 0U; > - for (i = 0U; i < uni->u_len; i++) { > + for (i = 0U; (i < uni->u_len) && ((u_len + 1 + u_ch) < length); i++) { > len = nls->char2uni(&uni->u_name[i], uni->u_len - i, &uni_char); > if (!len) > continue; > @@ -320,6 +323,7 @@ try_again: > if (uni_char > max_val) { > max_val = 0xffffU; > ocu[0] = (uint8_t)0x10U; > + u_ch = 2; > goto try_again; > } > > -- > 2.1.0 > > -- Jan Kara <jack@suse.com> SUSE Labs, CR
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