From e1a7680b960fe25821f2419b4c0b1215f8ab2f9b Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 16 Nov 2018 13:43:17 +0100 Subject: [PATCH] udf: Allow mounting volumes with incorrect identification strings Commit c26f6c615788 ("udf: Fix conversion of 'dstring' fields to UTF8") started to be more strict when checking whether converted strings are properly formatted. Sudip reports that there are DVDs where the volume identification string is actually too long - UDF reports: [ 632.309320] UDF-fs: incorrect dstring lengths (32/32) during mount and fails the mount. This is mostly harmless failure as we don't need volume identification (and even less volume set identification) for anything. So just truncate the volume identification string if it is too long and replace it with 'Invalid' if we just cannot convert it for other reasons. This keeps slightly incorrect media still mountable. CC: stable@vger.kernel.org Fixes: c26f6c615788 ("udf: Fix conversion of 'dstring' fields to UTF8") Reported-by: Sudip Mukherjee Signed-off-by: Jan Kara --- fs/udf/super.c | 16 ++++++++++------ fs/udf/unicode.c | 14 +++++++++++--- 2 files changed, 21 insertions(+), 9 deletions(-) diff --git a/fs/udf/super.c b/fs/udf/super.c index 8f2f56d9a1bb..0672382b79e3 100644 --- a/fs/udf/super.c +++ b/fs/udf/super.c @@ -827,16 +827,20 @@ static int udf_load_pvoldesc(struct super_block *sb, sector_t block) ret = udf_dstrCS0toChar(sb, outstr, 31, pvoldesc->volIdent, 32); - if (ret < 0) - goto out_bh; - - strncpy(UDF_SB(sb)->s_volume_ident, outstr, ret); + if (ret < 0) { + strcpy(UDF_SB(sb)->s_volume_ident, "Invalid"); + pr_warn("incorrect volume identification, setting to " + "'Invalid'\n"); + } else { + strncpy(UDF_SB(sb)->s_volume_ident, outstr, ret); + } udf_debug("volIdent[] = '%s'\n", UDF_SB(sb)->s_volume_ident); ret = udf_dstrCS0toChar(sb, outstr, 127, pvoldesc->volSetIdent, 128); - if (ret < 0) + if (ret < 0) { + ret = 0; goto out_bh; - + } outstr[ret] = 0; udf_debug("volSetIdent[] = '%s'\n", outstr); diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c index 45234791fec2..5fcfa96463eb 100644 --- a/fs/udf/unicode.c +++ b/fs/udf/unicode.c @@ -351,6 +351,11 @@ static int udf_name_to_CS0(struct super_block *sb, return u_len; } +/* + * Convert CS0 dstring to output charset. Warning: This function may truncate + * input string if it is too long as it is used for informational strings only + * and it is better to truncate the string than to refuse mounting a media. + */ int udf_dstrCS0toChar(struct super_block *sb, uint8_t *utf_o, int o_len, const uint8_t *ocu_i, int i_len) { @@ -359,9 +364,12 @@ int udf_dstrCS0toChar(struct super_block *sb, uint8_t *utf_o, int o_len, if (i_len > 0) { s_len = ocu_i[i_len - 1]; if (s_len >= i_len) { - pr_err("incorrect dstring lengths (%d/%d)\n", - s_len, i_len); - return -EINVAL; + pr_warn("incorrect dstring lengths (%d/%d)," + " truncating\n", s_len, i_len); + s_len = i_len - 1; + /* 2-byte encoding? Need to round properly... */ + if (ocu_i[0] == 16) + s_len -= (s_len - 1) & 2; } } -- 2.16.4