1 files changed, 43 insertions, 0 deletions
diff --git a/debian/patches/Use-only-half-of-detected-free-memory-on-systems-without-.patch b/debian/patches/Use-only-half-of-detected-free-memory-on-systems-without-.patch
new file mode 100644
index 0000000..caf47ce
--- /dev/null
+++ b/debian/patches/Use-only-half-of-detected-free-memory-on-systems-without-.patch
@@ -0,0 +1,43 @@
+From: Milan Broz <gmazyland@gmail.com>
+Date: Mon, 17 Apr 2023 13:41:17 +0200
+Subject: Use only half of detected free memory on systems without swap.
+
+As tests shows, limiting used Argon2 memory to free memory on
+systems without swap is still not enough.
+Use just half of it, this should bring needed margin while
+still use Argon2.
+
+Note, for very-low memory constrained systems user should
+avoid memory-hard PBKDF (IOW manually select PBKDF2), we
+do not do this automatically.
+
+Origin: https://gitlab.com/cryptsetup/cryptsetup/-/commit/6721d3a8b29b13fe88aeeaefe09d457e99d1c6fa
+Bug: https://gitlab.com/cryptsetup/cryptsetup/-/issues/802#note_1328592911
+Bug-Debian: https://bugs.debian.org/1028250
+---
+ lib/utils_pbkdf.c | 9 ++++++++-
+ 1 file changed, 8 insertions(+), 1 deletion(-)
+
+diff --git a/lib/utils_pbkdf.c b/lib/utils_pbkdf.c
+index b2d4fa0..7399bd2 100644
+--- a/lib/utils_pbkdf.c
++++ b/lib/utils_pbkdf.c
+@@ -76,10 +76,17 @@ uint32_t pbkdf_adjusted_phys_memory_kb(void)
+ 	memory_kb /= 2;
+ 
+ 	/*
+-	 * Never use more that available free space on system without swap.
++	 * Never use more that half of available free memory on system without swap.
+ 	 */
+ 	if (!crypt_swapavailable()) {
+ 		free_kb = crypt_getphysmemoryfree_kb();
++
++		/*
++		 * Using exactly free memory causes OOM too, use only half of the value.
++		 * Ignore small values (< 64MB), user should use PBKDF2 in such environment.
++		 */
++		free_kb /= 2;
++
+ 		if (free_kb > (64 * 1024) && free_kb < memory_kb)
+ 			return free_kb;
+ 	}