Avoid reading 1 byte off the end when the string does not contain a '\0' byte

[kevinbackhouse]

Fixes: #1887

Credit to OSS-Fuzz: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=37889

These three loops were followed by a ++i operation, which worked correctly when the string contained a '\0' byte, but advanced i to one byte beyond the end of the buffer when it didn't.

[kevinbackhouse]

@Mergifyio backport 0.27-maintenance

[mergify]

Command backport 0.27-maintenance: pending

Waiting for the pull request to get merged

[codecov]

Codecov Report

Merging #1888 (96516c8) into main (cb16324) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 96516c8 differs from pull request most recent head bd211a9. Consider uploading reports for the commit bd211a9 to get more accurate results

@@           Coverage Diff           @@
##             main    #1888   +/-   ##
=======================================
  Coverage   60.80%   60.81%           
=======================================
  Files          96       96           
  Lines       18963    18960    -3     
  Branches     9512     9512           
=======================================
- Hits        11531    11530    -1     
+ Misses       5131     5130    -1     
+ Partials     2301     2300    -1     

Impacted Files	Coverage Δ
src/crwimage_int.cpp	74.04% <100.00%> (+0.03%)	⬆️
src/crwimage.cpp	64.19% <0.00%> (+1.23%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update cb16324...bd211a9. Read the comment docs.

[kmilos]

LGTM

[mergify]

Command backport 0.27-maintenance: success

Backports have been created

• #1889 Avoid reading 1 byte off the end when the string does not contain a '\0' byte (backport #1888) has been created for branch 0.27-maintenance