Hit this kernel hang too while fuzzing. Please see this as a tentative patch indicating where the problem is -- I don't really know much about UDF or what an allocation extent is or whether there are more problems in the same neighbourhood. It looks like udf_truncate_extents() might also have a similar problem?
Signed-off-by: Vegard Nossum <[email protected]> Cc: [email protected] Cc: Jan Kara <[email protected]> Cc: Quentin Casasnovas <[email protected]> Cc: Andrew Morton <[email protected]> --- fs/udf/inode.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git fs/udf/inode.c fs/udf/inode.c index 8d0b3ad..e1875f5 100644 --- fs/udf/inode.c +++ fs/udf/inode.c @@ -2047,13 +2047,26 @@ void udf_write_aext(struct inode *inode, struct extent_position *epos, epos->offset += adsize; } +/* + * Maximum number of allocation extents. The chosen number is + * arbitrary - just that we hopefully don't limit any real use + * but avoid looping for too long on corrupted media. + */ +#define UDF_MAX_AEXT_NESTING 4096 + int8_t udf_next_aext(struct inode *inode, struct extent_position *epos, struct kernel_lb_addr *eloc, uint32_t *elen, int inc) { int8_t etype; + unsigned int indirections = 0; while ((etype = udf_current_aext(inode, epos, eloc, elen, inc)) == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) { + if (++indirections > UDF_MAX_AEXT_NESTING) { + udf_err(inode->i_sb, "too many AEXTs (max %u supported)\n", UDF_MAX_AEXT_NESTING); + return -1; + } + int block; epos->block = *eloc; epos->offset = sizeof(struct allocExtDesc); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
