Details
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Bug
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Status: Closed
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Major
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Resolution: Won't Fix
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1.0.1
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None
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None
Description
On fedora 28 the gcc 8.1.1 compiler gives this warning-as-error:
/home/aconway/dispatch/src/policy.c: In function '_qd_policy_link_user_name_subst':
/home/aconway/dispatch/src/policy.c:541:9: error: 'strncpy' output may be truncated copying between 0 and 8 bytes from a string of length 7 [-Werror=stringop-truncation]
strncpy(obuf, duser, copysize);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
The error is correct: the function is using strncpy to copy a string into a space that may be too small for it, resulting in an un-terminated string.
I fixed some similar issues already but I'm confused by what's going on here: it looks like we are searching for the uname parameter and replacing it with "${user}" which seems backwards.
The function would be simpler and clearer if it used snprintf rather than successive strncpy, i.e.
n = snprintf(obuf, osize, "%s%s%s", leading, duser, trailing);
but the problem of properly handling the error if the resulting string is too big for obuf remains.