cups-browsed gets SIGSEGV when generating PPD file

[zdohnal]

Hi,

we have an issue in Fedora about cups-browsed getting SIGSEGV when generating PPD file.

cups-browsed is set to BrowsePoll to CentOS 7 server, where a print queue with following ppd is installed. CUPS-1.6.3 from CentOS is not capable to return media-col-database via response, so Get-Printer-Attributes operation passes only with All keyword for requested attributes.

The attached gdb log shows ppdname contains A4 because media-col-default contains non-borderless value, but other attributes are missing (media-col-database) or are set as borderless (media-size-supported, media-supported).

Then the SIGSEGV comes in this code:

2224 
2225     if (all_borderless) {
2226       suffix = strcasestr(ppdname, ".Borderless");
2227       *suffix = '\0';
2228     }

all_borderless is still 1, because all medias in sizes are Borderless, but ppdname is A4, so it segfaults on *suffix = '\0'; because suffix is NULL.

The quick fix would be to check whether suffix is NULL, but it feels like narrow fix - what do you think about how the code should behave in situations when media-col-default tells non-borderless media and other medias are borderless?

[tillkamppeter]

Simple addition of NULL checks is OK here, as we only want to remove unneeded ".Borderless" suffixes.
Fixed in commit 240ffb9 in master. Merge to 1.x will come later.