In order to work with preprocessed dts files more easily, dts will parse
line number information in the form emitted by cpp.
Anton Blanchard (using a fuzzer) reported that including a line number
directive with a nul character (a literal nul in the input file, not a \0
sequence) would cause dtc to SEGV. I spotted several more problems on
examining the code:
* It modified yytext in place which seems to work, but is ugly and I'm
not sure if it's safe on all lex/flex versions
* The regexp used in the lexer to recognize line number information
accepts strings with escape characters, but it won't process these
escapes.
- GNU cpp at least, will generate \ escapes in line number
information, at least with files containing " or \ in the name
This patch reworks the handling of line number information to address
these problems. \ escapes should now be handled directly. nuls in file
names (either with a literal nul in the input file, or with a \0 escape
sequence) are still not permitted, but will now result in a lexical error
rather than a SEGV.
Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Previously, the #line parsing regex ended with ({WS}+[0-9]+)?. The {WS}
could match line-break characters. If the #line directive did not contain
the optional flags field at the end, this could cause any integer data on
the next line to be consumed as part of the #line directive parsing. This
could cause syntax errors (i.e. #line parsing consuming the leading 0
from a hex literal 0x1234, leaving x1234 to be parsed as cell data,
which is a syntax error), or invalid compilation results (i.e. simply
consuming literal 1234 as part of the #line processing, thus removing it
from the cell data).
Fix this by replacing {WS} with [ \t] so that it can't match line-breaks.
Convert all instances of {WS}, even though the other instances should be
irrelevant for any well-formed #line directive. This is done for
consistency and ultimate safety.
Reported-by: Ian Campbell <Ian.Campbell@citrix.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Line control directives of the following formats are supported:
#line LINE "FILE"
# LINE "FILE" [FLAGS]
This allows dtc to consume the output of pre-processors, and to provide
error messages that refer to the original filename, including taking
into account any #include directives that the pre-processor may have
performed.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
